Comprehensive Income (Loss) (Details) (USD $) In Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Comprehensive Income (Loss)
Net income	$ 538		$ 273		$ 325		$ 191
Investments	2		3		3		12
Reclassification into earnings	(278)				(432)
Change in fair value	(231)		(146)		293		(146)
Amortization of net actuarial (gains) losses	(8)		(3)		(13)		(6)
Other	1		(3)		4		(4)
Comprehensive income (loss) adjustments, before tax	(514)		(149)		(145)		(144)
Total comprehensive income (loss)	$ 24	[1]	$ 124	[1]	$ 180	[1]	$ 47	[1]

[1] There were no income tax effects for either period due to the recording of valuation allowance.