Derivatives and Hedging Activities (Details Textuals) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Derivatives And Hedging Activities Textuals [Abstract]
Net reduction in interest expense on long term debt	$ 17	$ 34	$ 39	$ 68
Derivative [Line Items]
Margin on interest rate swap not netted	152		152		$ 144
Derivative Instruments, Gain (Loss) [Line Items]
Net hedge ineffectiveness	0	0	0	0
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	16,900		16,900		14,800
Net Investment Hedging [Member]
Derivative [Line Items]
Effection portion of loss (gain) on hedges	40	(51)	168	(1)
Ineffectiveness reclassified from AOCI into income	0	0	0	0
Other expense [Member]
Derivative [Line Items]
Loss (gain) in Changes of Fair Value of Derivatives not designated as hedges	(6)	$ 1	(10)	$ 2
Individually Significant Counterparties [Member]
Offsetting Assets [Line Items]
Total derivatives assets,net	$ 0		$ 0		$ 0