Statements of Unaudited Condensed Consolidated Changes in Equity Statement - USD ($)  $ in Millions  | 
Total  | 
Common Stock [Member]  | 
Additional Paid-in Capital [Member]  | 
Retained Earnings [Member]  | 
Treasury Stock [Member]  | 
AOCI Attributable to Parent [Member]  | 
Noncontrolling Interest [Member]  | 
| Balance, beginning of period (in shares) at Dec. 31, 2018 | 
 
 | 
292,600,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period at Dec. 31, 2018 | 
$ 424.2
 | 
$ 37.7
 | 
$ 3,916.7
 | 
$ (3,060.2)
 | 
$ (186.1)
 | 
$ (283.9)
 | 
 
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 
(13.7)
 | 
 
 | 
 
 | 
(22.1)
 | 
 
 | 
8.4
 | 
 
 | 
| Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture | 
 
 | 
1,700,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture | 
(10.0)
 | 
 
 | 
(56.5)
 | 
 
 | 
46.5
 | 
 
 | 
 
 | 
| Stock Repurchased During Period, Shares | 
 
 | 
(11,500,000)
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Common Share Repurchases, Value | 
(124.3)
 | 
 
 | 
 
 | 
 
 | 
(124.3)
 | 
 
 | 
 
 | 
| Dividends, Common Stock | 
(14.5)
 | 
 
 | 
 
 | 
(14.5)
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period (in shares) at Mar. 31, 2019 | 
 
 | 
282,800,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period at Mar. 31, 2019 | 
$ 261.7
 | 
$ 37.7
 | 
3,860.2
 | 
(3,096.8)
 | 
(263.9)
 | 
(275.5)
 | 
 
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Common Stock, Dividends, Per Share, Declared | 
$ 0.05
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period (in shares) at Dec. 31, 2018 | 
 
 | 
292,600,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period at Dec. 31, 2018 | 
$ 424.2
 | 
$ 37.7
 | 
3,916.7
 | 
(3,060.2)
 | 
(186.1)
 | 
(283.9)
 | 
 
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 
$ 150.8
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Stock Repurchased During Period, Shares | 
(24,400,000)
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period (in shares) at Jun. 30, 2019 | 
 
 | 
270,000,000.0
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period at Jun. 30, 2019 | 
$ 285.6
 | 
$ 37.7
 | 
3,863.6
 | 
(2,952.6)
 | 
(391.3)
 | 
(271.8)
 | 
 
 | 
| Balance, beginning of period (in shares) at Mar. 31, 2019 | 
 
 | 
282,800,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period at Mar. 31, 2019 | 
261.7
 | 
$ 37.7
 | 
3,860.2
 | 
(3,096.8)
 | 
(263.9)
 | 
(275.5)
 | 
 
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 
164.5
 | 
 
 | 
 
 | 
160.8
 | 
 
 | 
3.7
 | 
 
 | 
| Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture | 
 
 | 
100,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture | 
4.6
 | 
 
 | 
3.4
 | 
 
 | 
1.2
 | 
 
 | 
 
 | 
| Stock Repurchased During Period, Shares | 
 
 | 
(12,900,000)
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Common Share Repurchases, Value | 
(128.6)
 | 
 
 | 
 
 | 
 
 | 
(128.6)
 | 
 
 | 
 
 | 
| Dividends, Common Stock | 
(16.6)
 | 
 
 | 
 
 | 
(16.6)
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period (in shares) at Jun. 30, 2019 | 
 
 | 
270,000,000.0
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period at Jun. 30, 2019 | 
$ 285.6
 | 
$ 37.7
 | 
3,863.6
 | 
(2,952.6)
 | 
(391.3)
 | 
(271.8)
 | 
 
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Common Stock, Dividends, Per Share, Declared | 
$ 0.05
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period (in shares) at Dec. 31, 2019 | 
270,084,005
 | 
270,100,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period at Dec. 31, 2019 | 
$ 357.9
 | 
$ 37.7
 | 
3,872.1
 | 
(2,842.4)
 | 
(390.7)
 | 
(318.8)
 | 
$ 0.0
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 
(46.9)
 | 
 
 | 
 
 | 
(52.1)
 | 
 
 | 
1.7
 | 
3.5
 | 
| Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture | 
 
 | 
1,700,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture | 
2.1
 | 
 
 | 
(23.6)
 | 
 
 | 
25.7
 | 
 
 | 
 
 | 
| Stock Issued During Period, Shares, Acquisitions | 
 
 | 
126,800,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Stock Issued During Period, Value, Acquisitions | 
947.4
 | 
$ 15.9
 | 
601.7
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Noncontrolling Interest, Increase from Business Combination | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
329.8
 | 
| Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders | 
(5.5)
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
(5.5)
 | 
| Dividends, Common Stock | 
(24.0)
 | 
 
 | 
 
 | 
(24.0)
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period (in shares) at Mar. 31, 2020 | 
 
 | 
398,600,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period at Mar. 31, 2020 | 
$ 1,231.0
 | 
$ 53.6
 | 
4,450.2
 | 
(2,918.5)
 | 
(365.0)
 | 
(317.1)
 | 
327.8
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Common Stock, Dividends, Per Share, Declared | 
$ 0.06
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period (in shares) at Dec. 31, 2019 | 
270,084,005
 | 
270,100,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period at Dec. 31, 2019 | 
$ 357.9
 | 
$ 37.7
 | 
3,872.1
 | 
(2,842.4)
 | 
(390.7)
 | 
(318.8)
 | 
0.0
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 
$ (143.8)
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Stock Issued During Period, Shares, Acquisitions | 
 
 | 
126,800,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period (in shares) at Jun. 30, 2020 | 
399,159,988
 | 
399,200,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period at Jun. 30, 2020 | 
$ 1,118.2
 | 
$ 53.6
 | 
4,443.6
 | 
(3,042.5)
 | 
(355.9)
 | 
(305.9)
 | 
325.3
 | 
| Balance, beginning of period (in shares) at Mar. 31, 2020 | 
 
 | 
398,600,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, beginning of period at Mar. 31, 2020 | 
1,231.0
 | 
$ 53.6
 | 
4,450.2
 | 
(2,918.5)
 | 
(365.0)
 | 
(317.1)
 | 
327.8
 | 
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Comprehensive Income (Loss), Net of Tax, Attributable to Parent | 
(96.9)
 | 
 
 | 
 
 | 
(123.9)
 | 
 
 | 
11.2
 | 
15.8
 | 
| Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture | 
 
 | 
600,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture | 
2.5
 | 
 
 | 
(6.6)
 | 
 
 | 
9.1
 | 
 
 | 
 
 | 
| Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders | 
(18.3)
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
(18.3)
 | 
| Dividends, Common Stock | 
$ (0.1)
 | 
 
 | 
 
 | 
(0.1)
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period (in shares) at Jun. 30, 2020 | 
399,159,988
 | 
399,200,000
 | 
 
 | 
 
 | 
 
 | 
 
 | 
 
 | 
| Balance, end of period at Jun. 30, 2020 | 
$ 1,118.2
 | 
$ 53.6
 | 
$ 4,443.6
 | 
$ (3,042.5)
 | 
$ (355.9)
 | 
$ (305.9)
 | 
$ 325.3
 |