Consolidated Statement of Shareholder's Interest (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Shareholder's Interest [Roll Forward]
Balance at beginning of period			$ 9,653	$ 8,896
Net income	275	296	639	591
Other comprehensive income/(loss), net of tax	(51)	(252)	(238)	(44)
Distributions			(28)	(300)
Balance at end of period	10,026	9,143	10,026	9,143
Shareholder's Interest [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period			5,274	5,274
Net income			0	0
Other comprehensive income/(loss), net of tax			0	0
Distributions			0	0
Balance at end of period	5,274	5,274	5,274	5,274
Accumulated Other Comprehensive Income/(Loss) (Note10) [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period			743	600
Net income			0	0
Other comprehensive income/(loss), net of tax			(238)	(44)
Distributions			0	0
Balance at end of period	505	556	505	556
Retained Earnings [Member]
Shareholder's Interest [Roll Forward]
Balance at beginning of period			3,636	3,022
Net income			639	591
Other comprehensive income/(loss), net of tax			0	0
Distributions			(28)	(300)
Balance at end of period	$ 4,247	$ 3,313	$ 4,247	$ 3,313