Derivatives and Hedging Activities (Details Textuals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivatives And Hedging Activities Textuals [Abstract]
Net reduction in interest expense	$ 126	$ 177	$ 187
Derivative [Line Items]
Ineffectiveness reclassified from AOCI into income	0	0	0
Margin on interest rate swap not netted	144	128
Derivative Instruments, Gain (Loss) Recognized in Income, Net		293	587
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	14,800	15,900
Net Investment Hedging [Member]
Derivative [Line Items]
Effection portion of gain (loss) on hedges	80	235	162
Credit Valuation Adjustment [Member]
Derivative [Line Items]
Notional amount of long-term debt	0	0
Other expense [Member]
Derivative [Line Items]
Gain (Loss) in Changes of Fair Value of Derivatives not designated as hedges	1	14	$ 87
Risk Exposure Low [Member]
Offsetting Assets [Line Items]
Total derivatives assets,net	0	0
Individually Significant Counterparties [Member]
Offsetting Assets [Line Items]
Total derivatives assets,net	$ 0	$ 0