Acquisitions (Details) - USD ($) $ in Millions		12 Months Ended
	Dec. 22, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Cash paid for acquisition		$ 46	$ 0	$ 0
Goodwill		$ 7,095	$ 7,086	$ 7,092
MLG
Business Acquisition [Line Items]
Cash paid for acquisition	$ 46
Net tangible assets	1
Definite-lived intangible assets	33
Goodwill	12
Total net assets recognized	$ 46