Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 94	$ 87
Securities available for sale:
Unrealized gains (losses) arising during the period, net of tax expense (benefit) of $7 and $(8)	24	(30)
Derivative instruments:
Unrealized (losses) gains arising during the period, net of tax (benefit) expense of $(2) and $1	(6)	4
Reclassification adjustment for (gains) losses included in net income, net of tax expense (benefit) of $0 and $0	(1)	0
Pension and postretirement benefit obligations:
Unrealized gains (losses) arising during the period, net of tax expense (benefit) of $0 and $0	1	0
Other Comprehensive Income (Loss)	18	(26)
Comprehensive Income	$ 112	$ 61