Stock-Based Plans - Stock Option Activity (Details) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($) $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Unrecognized compensation expense | $	$ 68
Stock Options
Stock Option Activity
Stock options outstanding, beginning of period (in shares)	10
Granted and assumed (in shares)	2
Exercised (in shares)	(5)
Forfeited/expired/canceled (in shares)	(1)
Distribution adjustment (in shares)	2
Stock options outstanding, end of period (in shares)	8
Weighted average exercise price of stock options granted during period (usd per share) | $ / shares	$ 48.99
Weighted average grant date fair value of options granted during period (usd per share) | $ / shares	$ 13.58