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 and other	$ 37	$ 59	$ 81	$ 118
Margin On Interest Rate Swap Not Netted	170		170		$ 169
Derivative [Line Items]
Notional amount of long-term debt	19,500		19,500		17,700
Effective portion of gain (loss) on hedges	(102)	135	(331)	43
Net hedge ineffectiveness	0	0
Other Expense [Member]
Derivative [Line Items]
Gain (Loss) in Changes of Fair Value of Derivatives not designated as hedges	(4)	6	(21)	(8)
Gain on embedded derivatives	(3)	0	(2)	6
Net Investment Hedges [Member] | Other Expense [Member]
Derivative [Line Items]
Amount reclassified from AOCI into income	0	5	0	5
Net hedge ineffectiveness	0	$ 0	0	$ 0
Not Sold Or Repledged [Member]
Derivative [Line Items]
Securities received as collateral	$ 0		$ 0		18
Risk Exposure Low [Member]
Derivative [Line Items]
Total derivative assets, net					$ 537