CONDENSED CONSOLIDATED STATEMENTS 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	$ 195	$ 453	$ 243	$ 1,228
Unrealized gains on available-for-sale debt securities:
Unrealized holding gains arising during period	456	577	1,338	1,007
Reclassification adjustment for net losses included in net income	0	0	0	1
Unrealized gains on cash flow hedge derivatives:
Unrealized holding gains arising during period	66	190	493	277
Reclassification adjustment for net (gains) losses included in net income	(49)	1	(74)	3
Defined benefit pension plans, net:
Reclassification of amounts to net periodic benefit costs	1	1	2	2
Other comprehensive income, net of tax	474	769	1,759	1,290
Comprehensive Income	$ 669	$ 1,222	$ 2,002	$ 2,518