Goodwill and Intangible Assets - Schedule of Future Estimated Amortization Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Abstract]
Amortization expense for intangible assets included in net income	$ 104	$ 107	$ 119
Future estimated amortization of intangibles
2016	87
2017	84
2018	77
2019	72
2020	$ 62
Minimum
Finite-Lived Intangible Assets [Abstract]
Useful lives of intangible assets	3 years
Maximum
Finite-Lived Intangible Assets [Abstract]
Useful lives of intangible assets	30 years