Consolidated Statement of Shareholder's Interest - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Shareholder's Interest [Roll Forward]
Balance at beginning of period			$ 11,367	$ 10,604
Shareholder's Interest Attributable to Noncontrolling Interest			0	0
Total Shareholder's Interest			11,367	10,604
Net income	$ 365	$ 718	1,011	1,294
Net Income (Loss) Attributable to Noncontrolling Interest			0	0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest			1,011	1,294
Other Comprehensive Income (Loss), Net of Tax	(275)	(335)	(561)	(332)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest			1	0
Distributions			(56)	(244)
Balance at end of period	11,760	11,322	11,760	11,322
Shareholder's Interest Attributable to Noncontrolling Interest	1	0	1	0
Total Shareholder's Interest	11,761	11,322	11,761	11,322
Shareholder's Interest [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period			5,227	5,217
Net income			0	0
Other Comprehensive Income (Loss), Net of Tax			0	0
Distributions			0	0
Balance at end of period	5,227	5,217	5,227	5,217
Accumulated Other Comprehensive Income/(Loss) (Note10) [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period			160	717
Net income			0	0
Other Comprehensive Income (Loss), Net of Tax	(275)	(335)	(562)	(332)
Distributions			0	0
Balance at end of period	(402)	385	(402)	385
Retained Earnings [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period			5,980	4,670
Net income			1,011	1,294
Other Comprehensive Income (Loss), Net of Tax			0	0
Distributions			(56)	(244)
Balance at end of period	$ 6,935	$ 5,720	6,935	5,720
Parent [Member]
Shareholder's Interest [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax			(562)	(332)
Distributions			(56)	(244)
Noncontrolling Interest [Member]
Shareholder's Interest [Roll Forward]
Distributions			$ 0	$ 0