Other Comprehensive Income (details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 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	$ 470	$ 687	$ 609	$ 1,226
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income, pretax	41	(9)	71	9
Net changes in benefit plan assets and obligations, pretax	22	20	64	57
Net changes in unrealized foreign currency translation and other changes, pretax	65	(180)	43	(94)
Other comprehensive income before income taxes	598	518	787	1,198
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income, tax expense (benefit)	162	239	212	428
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income, tax expense (benefit)	15	(3)	25	3
Net changes in benefit plan assets and obligations, tax expense (benefit)	7	7	22	20
Net changes in unrealized foreign currency translation and other changes, tax expense (benefit)	8	(46)	(3)	(30)
Other comprehensive income tax expense (benefit)	192	197	256	421
Change in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income, net of tax	308	448	397	798
Change in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income, net of tax	26	(6)	46	6
Net changes in benefit plan assets and obligations, net of tax	15	13	42	37
Net changes in unrealized foreign currency translation and other changes, net of tax	57	(134)	46	(64)
Other comprehensive income, net of taxes	$ 406	$ 321	$ 531	$ 777