Borrowings and Contractual Commitments Short-Term Borrowings (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Line Items]
Other Short-term Borrowings	$ 1,015	$ 1,024
Other Liabilities [Member]
Short-term Debt [Line Items]
Other Short-term Borrowings	$ 81	$ 0
Short-term Debt, Weighted Average Interest Rate	2.28%	0.00%
Master Notes [Member]
Short-term Debt [Line Items]
Other Short-term Borrowings	$ 483	$ 582
Short-term Debt, Weighted Average Interest Rate	0.25%	0.20%
Dealer Collateral [Member]
Short-term Debt [Line Items]
Other Short-term Borrowings	$ 451	$ 442
Short-term Debt, Weighted Average Interest Rate	0.55%	0.20%