Fair Values (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Investment securities:
Equity securities	$ 73	$ 78
Debt securities	19,869	8,328
Derivatives, gross	1,070	343
Total Assets	21,012	8,749
Liabilities
Derivatives, gross	422	440
Total Liabilities	422	440
Fair Value, Inputs, Level 1 [Member]
Investment securities:
Equity securities	72	77
Debt securities	7,214	0
Derivatives, gross	0	0
Total Assets	7,286	77
Liabilities
Derivatives, gross	0	0
Total Liabilities	0	0
Fair Value, Inputs, Level 2 [Member]
Investment securities:
Equity securities	1	1
Debt securities	12,655	8,328
Derivatives, gross	1,070	343
Total Assets	13,726	8,672
Liabilities
Derivatives, gross	422	440
Total Liabilities	422	440
Fair Value, Inputs, Level 3 [Member]
Investment securities:
Equity securities	0	0
Debt securities	0	0
Derivatives, gross	0	0
Total Assets	0	0
Liabilities
Derivatives, gross	0	0
Total Liabilities	$ 0	$ 0