Stock Based Awards and Other Equity Instruments - Additional Information (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Number of stock options issued	477,000
Total intrinsic value	$ 36	$ 7
Total fair value of stock options vested	$ 23	$ 20
Stock Options
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Number of stock options issued	476,826
Term of stock options	10 years
Stock options vest period	4 years
Closing stock price	$ 90.59
Grant-date fair value per option	$ 47.36	$ 22.68
Restricted Stock Units (RSUs)
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Stock options vest period	4 years
RSU's issued under incentive plan	459,999