Employee Benefit Plans - Postemployment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Defined Benefit Plan Disclosure [Line Items]
Net benefit cost	$ 5	$ 1	$ 431	$ 2
Postemployment Benefit Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Net service cost	4	3	12	10
Interest cost	0	2	2	6
Prior service cost (benefit)	(1)	(1)	(3)	(3)
Defined Benefit Plan Gross Periodic Benefit Cost	3	4	11	13
Severance Costs	0	61	(5)	61
Net benefit cost	3	$ 65	6	$ 74
Defined Benefit Plan, Contributions by Employer	13		33
Defined Benefit Plan Estimated Total Employer Contributions in Current Fiscal Year	$ 80		80
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			$ 47