Accumulated Other Comprehensive Income Reclassifications out of AOCI (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax	$ 9	$ 0	$ 11	$ (2)
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Tax	(3)	0	(4)	1
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	6	0	7	(1)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, before Tax	(99)	(101)	(302)	(315)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Tax	36	37	111	116
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	63	64	191	199
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	2	7	54	48
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	(1)	(3)	(20)	(18)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	(1)	(4)	(34)	(30)
Other Assets And Liabilities, Net [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	0	1	46	29
employee benefits [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax	$ 2	$ 6	$ 8	$ 19