Total Equity and Other Comprehensive Income (Accumulated Other Comprehensive Income (Loss) Components) (Details) - USD ($)	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Other Comprehensive Income [Abstract]
Net unrealized gains (losses) on non-OTTI securities, pretax	$ 731,000,000	$ 1,096,000,000	$ 1,022,000,000	$ 1,048,000,000	$ 836,000,000	$ 647,000,000
Net unrealized gains (losses) on non-OTTI securities, after-tax	463,000,000	694,000,000	647,000,000	663,000,000	529,000,000	409,000,000
Net unrealized gains (losses) on OTTI securities, before tax	122,000,000	118,000,000	115,000,000	143,000,000	102,000,000	36,000,000
Net unrealized gains (losses) on OTTI securities, after tax	78,000,000	76,000,000	74,000,000	92,000,000	65,000,000	24,000,000
Net unrealized gains (losses) on cash flow hedge derivatives, before tax	621,000,000	791,000,000	552,000,000	460,000,000	379,000,000	384,000,000
Net unrealized gains (losses) on cash flow hedge derivatives, after-tax	394,000,000	501,000,000	350,000,000	292,000,000	240,000,000	243,000,000
Pension and other postretirement benefit plan adjustments, before tax	(770,000,000)	(760,000,000)	(820,000,000)	(283,000,000)	(292,000,000)	(374,000,000)
Pension and other postretirement benefit plan adjustments, after-tax	(488,000,000)	(482,000,000)	(520,000,000)	(180,000,000)	(185,000,000)	(237,000,000)
Other, pretax	(95,000,000)	(86,000,000)	(59,000,000)	(13,000,000)	(9,000,000)	(20,000,000)
Other, after tax	(68,000,000)	$ (86,000,000)	(48,000,000)	$ 14,000,000	$ 7,000,000	$ (3,000,000)
Accumulated other comprehensive income (loss), pretax	609,000,000		810,000,000
Accumulated other comprehensive income (loss), after-tax	$ 379,000,000		$ 503,000,000