CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 581	$ 549	$ 823	$ 1,778
Unrealized gains on available-for-sale debt securities:
Unrealized holding gains (losses) arising during period	(32)	379	1,306	1,387
Reclassification adjustment for net gains included in net income	(34)	(2)	(34)	(2)
Unrealized gains on cash flow hedge derivatives:
Unrealized holding gains arising during period	1	83	494	361
Reclassification adjustment for net gains included in net income	(56)	(4)	(130)	(2)
Defined benefit pension plans, net:
Net actuarial loss arising during the year	(2)	0	(2)	0
Reclassification of amounts to net periodic benefit costs	3	1	5	3
Other comprehensive income, net of tax	(120)	457	1,639	1,747
Comprehensive Income	$ 461	$ 1,006	$ 2,462	$ 3,525