Description of Business, Including Segment and Geographic Area Information - Schedule of Revenue by Geographic Area (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 3,414	$ 3,675	$ 3,273	$ 3,008	$ 3,189	$ 3,429	$ 3,232	$ 3,150	$ 13,370	$ 13,000	$ 13,045
China (including Hong Kong)
Segment Reporting Information [Line Items]
Revenue									$ 6,000	$ 5,800	$ 5,700