CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Income	$ 694	$ 46
Unrealized gains on available-for-sale debt securities:
Unrealized holding (losses) gains arising during period	(700)	882
Reclassification adjustment for net losses included in net income	11	0
Unrealized gains on cash flow hedge derivatives:
Unrealized holding (losses) gains arising during period	(64)	427
Reclassification adjustment for net gains included in net income	(57)	(25)
Defined benefit pension plans, net:
Reclassification of amounts to net periodic benefit costs	1	1
Other comprehensive (loss) income, net of tax	(809)	1,285
Comprehensive (Loss) Income	$ (115)	$ 1,331