Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE MEASUREMENTS (Carrying Value And Fair Value Of Financial Instruments Disclosure) (Details)

v3.10.0.1
FAIR VALUE MEASUREMENTS (Carrying Value And Fair Value Of Financial Instruments Disclosure) (Details) - USD ($)
$ in Millions
Jun. 30, 2018
Dec. 31, 2017
Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value $ 2,378.0 $ 2,346.3
Fair Value [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value Adjustment to Interest Rate Hedge 1.2 1.4
Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 2,297.0 2,304.2
Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair Value Adjustment to Interest Rate Hedge 1.2 1.4
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 4.875% 2024 Senior Notes [Domain]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 388.5 398.0
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 5.90% 2020 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 88.4 88.0
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $500 million 4.80% 2020 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 120.5 118.8
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Note [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 124.6 130.8
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316 Million 1.5% 2025 Senior Notes [Domain]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 384.5 352.9
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $1,075 Million 5.75% 2025 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 1,028.6 1,029.3
Senior Notes [Member] | Fair Value [Member] | Fair Value, Inputs, Level 1 [Member] | $800 Million 6.25% 2040 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 241.7 227.1
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 4.875% 2024 Senior Notes [Domain]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 391.3 390.3
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $400 Million 5.90% 2020 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 88.1 88.6
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $500 million 4.80% 2020 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 122.0 122.0
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $700 Million 4.875% 2021 Senior Note [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 124.9 138.0
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $316 Million 1.5% 2025 Senior Notes [Domain]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 229.7 224.1
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $1,075 Million 5.75% 2025 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 1,047.1 1,047.2
Senior Notes [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 1 [Member] | $800 Million 6.25% 2040 Senior Notes [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 292.7 292.6
Line of Credit [Member] | Fair Value [Member] | Fair Value, Inputs, Level 2 [Member] | Revolving Credit Facility [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value 0.0 0.0
Line of Credit [Member] | Carrying Value [Member] | Fair Value, Inputs, Level 2 [Member] | Revolving Credit Facility [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Total long-term debt, fair value $ 0.0 $ 0.0