Income Taxes Income Taxes - Continuing Operations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 State and Local Jurisdiction [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Minimum [Member] State and Local Jurisdiction [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Maximum [Member] State and Local Jurisdiction [Member]
Income taxes related to adjustments included in common shareholder’s equity:
Benefit for income taxes related to continuing operations	$ (1,406)	$ (1,431)	$ (1,453)
Unrealized gains on securities available-for-sale, not other-than-temporarily impaired, net	7	13	26
Unrealized gains (losses) on other-than-temporarily impaired debt securities available-for-sale	1	3	(3)
Unrealized gains on cash flow hedging instruments	75	52	43
Changes in funded status of postretirement benefit plans	(8)	(6)	(5)
Foreign currency translation adjustment	1	(1)	2
Total	(1,330)	(1,370)	(1,390)
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current provision (benefit)	(958)	(772)	(1,684)
Deferred provision (benefit)	(448)	(659)	231
Total income tax expense (benefit)	(1,406)	(1,431)	(1,453)
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred income tax (benefit) provision (excluding the effects of other components)	(597)	(602)	148
(Decrease) increase in valuation allowance	323	(65)	49
(Increase) decrease in State operating loss carryforwards and credits	(296)	(65)	(8)
Foreign and general business tax credits	122	73	42
Deferred income tax (benefit) provision	$ (448)	$ (659)	$ 231
State net operating loss carryforward period				15 years	15 years	15 years	20 years	20 years