Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net income for the period	$ 238	$ 139
Other comprehensive income, net of tax:
Unrealized holding gains (losses) on investment securities	(126)	12
Net unrealized gains on other noninterest-bearing investments	1	1
Net unrealized holding gains (losses) on derivative instruments	(3)	(1)
Reclassification adjustment for increase in interest income recognized in earnings on derivatives instruments	0	(1)
Other comprehensive income (loss)	(128)	11
Comprehensive income	$ 110	$ 150