Goodwill and Intangible Assets - Textual Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment	$ 1,841	$ 0	$ 1,841	$ 0
Amortization expense for intangible assets included in net income	$ 20	$ 25	42	$ 51
Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	30 years
Customer Relationships and Trade Names
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived			$ 101