Consolidated Statement of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (40)	$ 557	$ 560	$ 1,353
Other comprehensive income:
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income (loss)	2,359	1,108	1,784	2,524
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income (loss)	3	(4)	(3)	1
Net changes in benefit plan assets and obligations	21	14	44	26
Net changes in unrealized foreign currency translation	52	5	(216)	55
Other comprehensive income before income taxes	2,435	1,123	1,609	2,606
Income tax expense	504	235	367	541
Other comprehensive income, net of taxes	1,931	888	1,242	2,065
Comprehensive income	$ 1,891	$ 1,445	$ 1,802	$ 3,418