Consolidated Statements of Stockholders' (Deficit) Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]
Treasury Stock, Shares						47,300,000
Beginning balance at Dec. 31, 2018	$ (149,600,000)	$ 900,000	$ 1,078,800,000	$ 1,855,000,000.0	$ (188,800,000)	$ (2,895,500,000)
Net income	294,700,000			294,700,000
Dividends, Common Stock, Cash	(85,000,000.0)			(85,000,000.0)
Change in cash flow hedges, net of tax expense	3,300,000				3,300,000
Foreign currency translation adjustments	(300,000)				(300,000)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	58,600,000				58,600,000
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	15,600,000		15,600,000
Stock Issued During Period, Value, Treasury Stock Reissued	2,600,000		(4,400,000)			$ 7,000,000.0
Stock Issued During Period, Shares, Treasury Stock Reissued						(200,000)
Treasury Stock, Shares, Acquired						1,500,000
Treasury Stock, Value, Acquired, Cost Method	(416,900,000)					$ (416,900,000)
Ending balance at Sep. 30, 2019	$ (277,300,000)	900,000	1,090,000,000.0	2,064,400,000	(127,200,000)	$ (3,305,400,000)
Cumulative Effect Period Of Adoption				(300,000)
Earnings Per Share, Diluted	$ 7.46
Dividends	$ 2.18
Change in cash flow hedges, tax expense	1,300,000
Pension and post-retirement liability changes, tax expense	16,400,000
Treasury Stock, Shares						48,100,000
Beginning balance at Jun. 30, 2019	(217,500,000)	900,000	1,085,800,000	1,979,400,000	(129,600,000)	$ (3,154,000,000.0)
Net income	114,700,000			114,700,000
Dividends, Common Stock, Cash	(29,700,000)			(29,700,000)
Change in cash flow hedges, net of tax expense	(400,000)				(400,000)
Foreign currency translation adjustments	(6,200,000)				(6,200,000)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	9,000,000.0				9,000,000.0
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	4,200,000		4,200,000
Stock Issued During Period, Value, Treasury Stock Reissued	1,000,000.0		$ 0			$ 1,000,000.0
Stock Issued During Period, Shares, Treasury Stock Reissued						0
Treasury Stock, Shares, Acquired			0			500,000
Treasury Stock, Value, Acquired, Cost Method	(152,400,000)					$ (152,400,000)
Ending balance at Sep. 30, 2019	$ (277,300,000)	900,000	$ 1,090,000,000.0	2,064,400,000	(127,200,000)	$ (3,305,400,000)
Earnings Per Share, Diluted	$ 2.94
Dividends	$ 0.77
Change in cash flow hedges, tax expense	$ 100,000
Treasury Stock, Shares						48,600,000
Treasury Stock, Shares	48,575,901					48,600,000
Beginning balance at Dec. 31, 2019	$ (170,200,000)	900,000	1,093,500,000	2,148,700,000	(103,800,000)	$ (3,309,500,000)
Net income	244,600,000			244,600,000
Dividends, Common Stock, Cash	(88,300,000)			(88,300,000)
Change in cash flow hedges, net of tax expense	1,700,000				1,700,000
Foreign currency translation adjustments	(11,800,000)				(11,800,000)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	200,000				200,000
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	18,400,000		18,400,000
Stock Issued During Period, Value, Treasury Stock Reissued	2,300,000		(2,500,000)			$ 4,800,000
Stock Issued During Period, Shares, Treasury Stock Reissued						(200,000)
Treasury Stock, Shares, Acquired						500,000
Treasury Stock, Value, Acquired, Cost Method	(110,100,000)					$ (110,100,000)
Ending balance at Sep. 30, 2020	(115,700,000)	900,000	1,109,400,000	2,303,700,000	(114,900,000)	$ (3,414,800,000)
Cumulative Effect Period Of Adoption	$ (1,300,000)			(1,300,000)
Earnings Per Share, Diluted	$ 6.34
Dividends	$ 2.31
Change in cash flow hedges, tax expense	500,000
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	(1,200,000)				(1,200,000)
Treasury Stock, Shares						48,900,000
Beginning balance at Jun. 30, 2020	(228,900,000)	900,000	1,102,400,000	2,201,500,000	(121,700,000)	$ (3,412,000,000.0)
Net income	131,700,000			131,700,000
Dividends, Common Stock, Cash	(29,500,000)			(29,500,000)
Change in cash flow hedges, net of tax expense	2,300,000				2,300,000
Foreign currency translation adjustments	6,000,000.0				6,000,000.0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	(300,000)				(300,000)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	8,000,000.0		8,000,000.0
Stock Issued During Period, Value, Treasury Stock Reissued	700,000		(1,000,000.0)			$ 1,700,000
Stock Issued During Period, Shares, Treasury Stock Reissued						(100,000)
Treasury Stock, Shares, Acquired						100,000
Treasury Stock, Value, Acquired, Cost Method	(4,500,000)					$ (4,500,000)
Ending balance at Sep. 30, 2020	$ (115,700,000)	$ 900,000	$ 1,109,400,000	$ 2,303,700,000	(114,900,000)	$ (3,414,800,000)
Earnings Per Share, Diluted	$ 3.42
Dividends	$ 0.77
Change in cash flow hedges, tax expense	1,300,000
Pension and post-retirement liability changes, tax expense	100,000
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	$ (1,200,000)				$ (1,200,000)
Treasury Stock, Shares	48,883,807					48,900,000