Other Comprehensive Income (details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Other Comprehensive Income disclosure
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income, pretax	$ 216	$ 645	$ 139	$ 539
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income, pretax	5	(10)	30	18
Net changes in benefit plan assets and obligations, pretax	22	19	42	37
Net changes in unrealized foreign currency translation and other changes, pretax	(86)	16	(22)	86
Other comprehensive income before income taxes	157	670	189	680
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income, tax expense (benefit)	77	224	50	189
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income, tax expense (benefit)	1	(4)	10	6
Net changes in benefit plan assets and obligations, tax expense (benefit)	8	7	15	13
Net changes in unrealized foreign currency translation and other changes, tax expense (benefit)	(20)	4	(11)	16
Other comprehensive income tax expense (benefit)	66	231	64	224
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income, net of tax	139	421	89	350
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income, net of tax	4	(6)	20	12
Net changes in benefit plan assets and obligations, net of tax	14	12	27	24
Net changes in unrealized foreign currency translation and other changes, net of tax	(66)	12	(11)	70
Other comprehensive income, net of taxes	$ 91	$ 439	$ 125	$ 456