Borrowings - Interest on Debt (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Interest on Debt
Cost of financing	$ 432	$ 407
Interest expense	523	346
Net investment derivative activity	(51)	(6)
Interest capitalized	3
Interest capitalized		(1)
Total interest paid and accrued	$ 907	$ 746