Stock-Based Incentive Plan (Stock Option Activity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of shares under option, outstanding at beginning of period	16,616,617
Weighted average exercise price per share, outstanding at beginning of period	$ 19.54
Number of shares under option - options granted	1,168,837
Weighted average exercise price per share - options granted	$ 30.62
Number of shares under option - options exercised	(1,607,628)
Weighted average exercise price per share - options exercised	$ 17.86
Number of shares under option - options forfeited	(188,576)
Weighted average exercise price per share - options forfeited	$ 22.13
Number of shares under option, outstanding at end of period	15,989,250
Weighted average exercise price per share, outstanding at end of period	$ 20.49
Number of shares under option - vested and expected to vet at March 31, 2013	15,084,161
Weighted average exercise price per share - vested and expected to vest at March 31, 2013	$ 20.35
Number of shares under option - options exercisable at March 31, 2013	9,774,159
Weighted average exercise price per share - options exercisable at March 31, 2013	$ 18.51