Stock-Based Compensation Plans - Summary of Information of Stock Options Exercised (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common Stock [Abstract]
Aggregate value	[1]	$ 11	$ 0	$ 3
Cash received for exercise price		$ 19	$ 0	$ 7

[1] Includes stock options issued to retirement eligible employees.