Statement 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
Net income	346.4
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	0.0
Net income	276.0				276.0
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.7	0.0
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	26.2	$ 0.2	$ (1.7)	27.7
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	38.1			38.1
Treasury Stock, Shares, Acquired		1.0
Treasury Stock, Value, Acquired, Par Value Method	111.8	$ 0.3	$ 111.8	(0.3)
Stock Repurchased During Period, Shares			1.0
Dividends	58.5				58.5
Other Comprehensive Income (Loss), Net of Tax	0.3					0.3
Common stock, shares outstanding		182.1
Stockholders' Equity Attributable to Parent	$ 4,070.2	$ 45.5	$ (2,255.7)	3,002.4	3,286.8	(8.8)
Treasury Stock, Shares			45.9
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
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)
Net income	$ 498.8
Treasury Stock, Shares, Acquired	5.7
Treasury Stock, Value, Acquired, Par Value Method	$ 425.5
Common stock, shares outstanding		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
Net income	214.0				214.0
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.3	0.1
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	14.2	$ 0.1	$ (1.5)	15.5
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	$ 21.8			21.8
Treasury Stock, Shares, Acquired	1.7	1.7
Treasury Stock, Value, Acquired, Par Value Method	$ 141.5	$ 0.4	$ 141.5	(0.5)
Stock Repurchased During Period, Shares			1.7
Dividends	66.0				66.0
Other Comprehensive Income (Loss), Net of Tax	$ (0.1)					(0.1)
Common stock, shares outstanding	172.7	172.7
Stockholders' Equity Attributable to Parent	$ 4,080.9	$ 43.2	$ (3,179.1)	$ 3,126.2	$ 4,098.7	$ (8.1)
Treasury Stock, Shares			57.0