Derivative Financial Instruments - Balance Sheet Offsetting, Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Derivative Liabilities
Gross Amounts of Recognized Liabilities	$ 218	$ 237
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	218	237
Financial Instruments (Collateral)	(93)	(85)
Cash Collateral Pledged	(64)	(71)
Net Amount	61	81
Repurchase, securities lending, and similar arrangements
Securities Sold under Agreements to Repurchase, Gross	0	0
Securities Sold under Agreements to Repurchase, Asset	0	0
Securities Sold under Agreements to Repurchase	0	0
Financial Instruments (Collateral)	0	0
Cash Collateral Pledged	0	0
Net Amount	0	0
Total
Gross Amounts of Recognized Liabilities	218	237
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	218	237
Financial Instruments (Collateral)	(93)	(85)
Cash Collateral Pledged	(64)	(71)
Net Amount	61	81
Interest rate swaps
Derivative Liabilities
Gross Amounts of Recognized Liabilities	2	0
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	2	0
Derivative Liability, Not Offset, Policy Election Deduction	(2)	0
Cash Collateral Pledged	0	0
Net Amount	0	0
Foreign exchange forwards
Derivative Liabilities
Gross Amounts of Recognized Liabilities	155	208
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	155	208
Derivative Liability, Not Offset, Policy Election Deduction	(54)	(84)
Cash Collateral Pledged	(42)	(45)
Net Amount	59	79
Client foreign currency options
Derivative Liabilities
Gross Amounts of Recognized Liabilities	2	2
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	2	2
Derivative Liability, Not Offset, Policy Election Deduction	0	(1)
Cash Collateral Pledged	(1)	0
Net Amount	1	1
Client interest rate derivatives
Derivative Liabilities
Gross Amounts of Recognized Liabilities	59	27
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Liabilities Presented in the Statement of Financial Position	59	27
Derivative Liability, Not Offset, Policy Election Deduction	(37)	0
Cash Collateral Pledged	(21)	(26)
Net Amount	$ 1	$ 1