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]
Common stock, shares outstanding		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
Net income	284.9				284.9
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.7	0.2
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	(14.4)	$ 0.1	$ (19.6)	5.1
APIC, Share-based Payment Arrangement, Increase for Cost 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	643.0
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
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	21.8			21.8
Treasury Stock, Shares, Acquired		(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
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
Net income	144.1				144.1
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.2	0.0
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	7.1	$ 0.0	$ (0.7)	7.8
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	19.0			19.0
Treasury Stock, Shares, Acquired		(1.2)
Treasury Stock, Value, Acquired, Par Value Method	(85.8)	$ (0.3)	$ (85.8)	0.2
Stock Repurchased During Period, Shares			1.2
Dividends	(65.7)				(65.7)
Other Comprehensive Income (Loss), Net of Tax	0.3					0.3
Common stock, shares outstanding		171.6
Stockholders' Equity Attributable to Parent	$ 4,099.9	$ 42.9	$ (3,265.6)	3,153.3	4,177.1	(7.8)
Treasury Stock, Shares			58.2
Common stock, shares outstanding	170.1	170.1
Stockholders' Equity Attributable to Parent	$ 4,122.3	$ 42.5	$ (3,412.9)	3,188.0	4,312.6	(7.9)
Treasury Stock, Shares			60.1
Net income	257.1				257.1
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		1.1	0.3
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	8.2	$ 0.3	$ (26.7)	34.6
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	29.1			29.1
Treasury Stock, Shares, Acquired		(0.7)
Treasury Stock, Value, Acquired, Par Value Method	(74.2)	$ (0.2)		0.2
Stock Repurchased During Period, Shares			0.7
Dividends	(75.1)				(75.1)
Other Comprehensive Income (Loss), Net of Tax	0.1					(0.1)
Net income	$ 567.9
Treasury Stock, Shares, Acquired	(4.6)
Treasury Stock, Value, Acquired, Par Value Method	$ (416.5)
Common stock, shares outstanding		170.5
Stockholders' Equity Attributable to Parent	4,267.3	$ 42.6	$ (3,513.8)	3,251.9	4,494.6	(8.0)
Treasury Stock, Shares			61.1
Net income	181.1				181.1
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.3	0.0
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	18.5	$ 0.1	$ (2.0)	20.4
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	34.1			34.1
Treasury Stock, Shares, Acquired		(3.2)
Treasury Stock, Value, Acquired, Par Value Method	(283.8)	$ (0.8)		0.8
Stock Repurchased During Period, Shares			3.2
Dividends	(74.9)				(74.9)
Other Comprehensive Income (Loss), Net of Tax	(0.5)					0.5
Common stock, shares outstanding		167.6
Stockholders' Equity Attributable to Parent	4,142.8	$ 41.9	$ (3,799.6)	3,307.2	4,600.8	(7.5)
Treasury Stock, Shares			64.3
Net income	129.7				129.7
StockIssuedDuringPeriodSharesShareBasedCompensationNetofRelatedTaxes(inshares)		0.2	0.0
StockIssuedDuringPeriodValueShareBasedCompensationNetofRelatedTaxes	6.8	$ 0.1	$ (2.2)	8.9
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	$ 35.2			35.2
Treasury Stock, Shares, Acquired	(0.7)	(0.7)
Treasury Stock, Value, Acquired, Par Value Method	$ (58.5)	$ (0.2)		0.2
Stock Repurchased During Period, Shares			0.7
Dividends	(73.5)				(73.5)
Other Comprehensive Income (Loss), Net of Tax	$ 0.1					(0.1)
Common stock, shares outstanding	167.1	167.1
Stockholders' Equity Attributable to Parent	$ 4,182.4	$ 41.8	$ (3,860.3)	$ 3,351.5	$ 4,657.0	$ (7.6)
Treasury Stock, Shares			65.0