CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 253	$ 453	$ 287	$ 892
Other comprehensive income (loss):
Net unrealized derivative instruments (losses) gains arising during the periods, net of income taxes of ($3), $23, $30 and $36, respectively	(8)	68	88	107
Reclassification adjustment for net derivative (gains) losses included in net income, net of income taxes of ($11), $4, ($12) and $9, respectively	(34)	15	(37)	30
Net unrealized debt securities gains arising during the periods, net of income taxes of $16, $72, $145 and $152, respectively	49	221	449	467
Other-than-temporary impairment not recognized in earnings on debt securities, net of income taxes of $0, $0, $0 and $0, respectively	0	1	0	1
Reclassification of net debt securities gains to net income, net of income taxes of ($1), ($1), ($1) and ($3), respectively	(2)	(3)	(2)	(8)
Amortization of actuarial loss, net of income taxes of $0, $1, $1 and $3, respectively	4	3	7	6
Net other comprehensive income	9	305	505	603
Total comprehensive income	$ 262	$ 758	$ 792	$ 1,495