Employee Benefit Plans (Details) (USD $) In Millions, except Per Share data	6 Months Ended
	Jun. 30, 2011
Activity under all stock option incentive plans
Beginning Balance, Number of Shares	78
Beginning Balance, Weighted Average Exercise Price per Share	$ 27.05
Beginning Balance, Weighted Average Grant Date Fair Value per Share	$ 15.05
Number of Shares, Options Granted	0	[1]
Weighted Average Exercise Price per Share, Options Granted	$ 45.82
Weighted Average Grant Date Fair Value per Share, Options Granted	$ 11.72
Number of Shares, Options Cancelled	(2)
Weighted Average Exercise Price per Share, Options Cancelled	$ 28.36
Weighted Average Grant Date Fair Value per Share, Options Cancelled	$ 11.86
Number of Shares, Options Exercised	(6)
Weighted Average Exercise Price per Share, Options Exercised	$ 23.92
Weighted Average Grant Date Fair Value per Share, Options Exercised	$ 14.77
Ending Balance, Number of Shares	70
Ending Balance, Weighted Average Exercise Price per Share	$ 27.31
Ending Balance, Weighted Average Grant Date Fair Value per Share	$ 15.2
Exercise Price Range Lower Range Limit [Member]
Activity under all stock option incentive plans
Beginning Balance, Exercise Price Range per Share	$ 0.01
Exercise Price Range per Share, Options Granted	$ 45.82
Exercise Price Range per Share, Options Cancelled	$ 0.55
Exercise Price Range per Share, Options Exercised	$ 0.01
Ending Balance, Exercise Price Range per Share	$ 0.01
Exercise Price Range Upper Range Limit [Member]
Activity under all stock option incentive plans
Beginning Balance, Exercise Price Range per Share	$ 48.63
Exercise Price Range per Share, Options Granted	$ 45.82
Exercise Price Range per Share, Options Cancelled	$ 46.01
Exercise Price Range per Share, Options Exercised	$ 45.05
Ending Balance, Exercise Price Range per Share	$ 48.63

[1] Less than one million stock options were granted in the six months ended June 30, 2011.