Income Taxes (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Total income tax (benefit) expense and the resulting effective tax rate
Income (loss) before income taxes times 35% statutory federal tax rate	$ 471	$ 278	$ (804)
Federal income tax rate	35.00%	35.00%	35.00%
Amortization of tax-advantaged investments	65	59	53
Amortization of tax-advantaged investments, rate	4.80%	7.40%	(2.30%)
Amortization of nondeductible intangibles	0		38
Amortization of nondeductible intangibles, rate	0.00%		(1.70%)
Foreign tax adjustments	17	24	9
Foreign tax adjustments, rate	1.30%	3.00%	(0.40%)
Reduced tax rate on lease financing income	0	6	(16)
Reduced tax rate on lease financing income, rate	0.00%	0.80%	0.70%
Tax-exempt interest income	(16)	(17)	(17)
Tax-exempt interest income, rate	(1.20%)	(2.10%)	0.80%
Corporate-owned life insurance income	(42)	(48)	(40)
Corporate-owned life insurance income, rate	(3.10%)	(6.00%)	1.70%
Increase (decrease) in tax reserves	2	(6)	(53)
Increase (decrease) in tax reserves, rate	0.10%	(0.80%)	2.30%
Interest refund (net of federal tax benefit)	(24)
Interest refund (net of federal tax benefit), rate	(1.80%)
State income tax, net of federal tax benefit	(1)	5	(86)
State income tax, net of federal tax benefit, rate	0.00%	0.60%	3.70%
Tax credits	(125)	(117)	(106)
Tax credits, rate	(9.30%)	(14.70%)	4.60%
Other	22	2	(13)
Other, rate	1.60%	0.20%	0.60%
Income tax (benefit) expense	369	186	(1,035)
Total income tax expense (benefit), rate	27.40%	23.40%	45.00%
The change in liability for unrecognized tax benefits
Balance at beginning of year	23	21
Increase for other tax positions of prior years	7	2
Decrease related to other settlements with taxing authorities	(22)
Balance at end of year	$ (8)	$ 23	$ 21