Consolidated Statements of Stockholders' Equity Statement - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Deferred Tax Asset [Domain]
Common stock, shares outstanding		183.1
Stockholders' Equity Attributable to Parent	$ 4,065.7	$ 45.8	$ (1,925.0)	$ 2,893.8	$ 3,059.6	$ (8.5)
Treasury Stock, Shares			42.9
Net income	70.4				70.4
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.9	0.4
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	(29.8)	$ 0.2	$ (44.7)	14.7
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	25.5			27.4
Treasury Stock, Shares, Acquired		(1.6)
Treasury Stock, Value, Acquired, Par Value Method	(172.5)	$ (0.4)	$ (172.5)	0.4
Stock Repurchased During Period, Shares			1.6
Dividends	(58.8)				(58.8)
Other Comprehensive Income (Loss), Net of Tax	0.0					0.0
Common stock, shares outstanding		182.4
Stockholders' Equity Attributable to Parent	3,900.5	$ 45.6	$ (2,142.2)	2,936.3	3,069.3	(8.5)
Treasury Stock, Shares			44.9
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 18.5
Common stock, shares outstanding	177.4	177.4
Stockholders' Equity Attributable to Parent	$ 4,097.0	$ 44.4	$ (2,732.5)	3,061.0	3,732.9	(8.8)
Treasury Stock, Shares			51.0
Cumulative Effect of New Accounting Principle in Period of Adoption							$ (1.9)
Net income	284.9				284.9
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.7	0.2
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	(14.4)	$ 0.1	$ (19.6)	5.1
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	$ 21.3			21.3
Treasury Stock, Shares, Acquired	(4.0)	(4.0)
Treasury Stock, Value, Acquired, Par Value Method	$ (284.0)	$ (1.0)	$ (284.0)	1.0
Stock Repurchased During Period, Shares			4.0
Dividends	(67.1)				(67.1)
Other Comprehensive Income (Loss), Net of Tax	$ 0.6					0.6
Common stock, shares outstanding	174.1	174.1
Stockholders' Equity Attributable to Parent	$ 4,038.3	$ 43.5	$ (3,036.1)	$ 3,088.4	$ 3,950.7	$ (8.2)
Treasury Stock, Shares			55.2