CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - 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	$ 83	$ 103	$ 214	$ 292
Securities available for sale:
Unrealized gains (losses) arising during the period, net of tax expense (benefit) of $(1) and $1, $18 and $17	(3)	6	63	60
Derivative instruments:
Unrealized gains (losses) arising during the period, net of tax expense (benefit) of $2 and $(1), $(9) and $(7)	8	(4)	(32)	(24)
Reclassification adjustment for gains (losses) included in net income, net of tax expense (benefit) of $(1) and $0, $(2) and $0	4	0	7	(1)
Pension and postretirement benefit obligations:
Unrealized gains arising during the period, net of tax expense of $0 and $0, $0 and $0	0	1	1	2
Other Comprehensive Income	9	3	39	37
Comprehensive Income	$ 92	$ 106	$ 253	$ 329