Derivatives and Hedging Activities (Details Textuals) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Derivatives And Hedging Activities Textuals [Abstract]
Net reduction in interest expense	$ 44	$ 50	$ 86	$ 95
Derivative [Line Items]
Ineffectiveness reclassified from AOCI into income	0	0	0	0
Margin on interest rate swap not netted	103		103		$ 91
Fair Value Hedging [Member]
Derivative [Line Items]
Notional amount of long-term debt	15,200		15,200		14,700
Net Investment Hedging [Member]
Derivative [Line Items]
Effection portion of gain (loss) on hedges	22	$ (50)	85	$ (126)
Credit Valuation Adjustment [Member]
Derivative [Line Items]
Notional amount of long-term debt	0		0		0
None Sold or Repledged [Member]
Offsetting Assets [Line Items]
Securities received as collateral	0		0		40
Individually Significant Counterparties [Member]
Offsetting Assets [Line Items]
Total derivatives assets,net	$ 0		$ 0		$ 0