Software Development and Intellectual Property Licenses (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Software development and intellectual property licenses:
Internally-developed software costs	$ 284		$ 284		$ 266
Payments made to third-party software developers	153		153		150
Total software development costs	437		437		416
Intellectual property licenses	4		4		$ 30
Amortization:
Amortization of capitalized software development costs and intellectual property licenses	$ 115	$ 85	$ 265	$ 232