Fair Values (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Investment securities:
Equity securities and other	$ 48	$ 48
Debt securities		3,111
Derivative assets	514	210
Total assets	5,161	3,369
Liabilities
Derivative liabilities	214	218
Total derivatives	214	218
Level 1 [Member]
Investment securities:
Equity securities and other	1	1
Debt securities	0	1,045
Derivative assets	0	0
Total assets	1	1,046
Liabilities
Derivative liabilities	0	0
Total derivatives	0	0
Level 2 [Member]
Investment securities:
Equity securities and other	47	47
Debt securities	4,599	2,066
Derivative assets	514	210
Total assets	5,160	2,323
Liabilities
Derivative liabilities	214	218
Total derivatives	214	218
Level 3 [Member]
Investment securities:
Equity securities and other	0	0
Debt securities	0	0
Derivative assets	0	0
Total assets	0	0
Liabilities
Derivative liabilities	0	0
Total derivatives	$ 0	$ 0