Total Equity and Other Comprehensive Income (Accumulated Other Comprehensive Income (Loss) Components) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Other Comprehensive Income [Abstract]
Net unrealized gains (losses) on non-OTTI securities, pretax	$ 1,048	$ 836	$ 647	$ 895	$ 1,688	$ 1,858
Net unrealized gains (losses) on non-OTTI securities, after-tax	663	529	409	563	1,069	1,177
Net unrealized gains (losses) on OTTI securities, before tax	143	102	36	(99)	(54)	(195)
Net unrealized gains (losses) on OTTI securities, after tax	92	65	24	(62)	(33)	(123)
Net unrealized gains (losses) on cash flow hedge derivatives, before tax	460	379	384	523	804	911
Net unrealized gains (losses) on cash flow hedge derivatives, after-tax	292	240	243	332	510	578
Pension and other postretirement benefit plan adjustments, before tax	(283)	(292)	(374)	(1,173)	(1,180)	(1,226)
Pension and other postretirement benefit plan adjustments, after-tax	(180)	(185)	(237)	(744)	(748)	(777)
Other, pretax	(13)	(9)	(20)	(54)	(47)	(41)
Other, after tax	14	7	(3)	(44)	(31)	(21)
Accumulated other comprehensive income (loss), pretax	1,355		673
Accumulated other comprehensive income (loss), after-tax	$ 881		$ 436