Derivative Financial Instruments - Balance Sheet Offsetting, Assets (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Derivative Assets
Gross Amounts of Recognized Assets	$ 258	$ 285
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	258	285
Financial Instruments (Collateral)	(113)	(145)
Cash Collateral Received	(34)	(21)
Net Amount	111	119
Reverse repurchase, securities borrowing, and similar arrangements
Gross Amounts of Recognized Assets	762	227
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	762	227
Financial Instruments (Collateral)	(762)	(227)
Cash Collateral Received	0	0
Net Amount	0	0
Total
Gross Amounts of Recognized Assets	1,020	512
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	1,020	512
Financial Instruments (Collateral)	(875)	(372)
Cash Collateral Received	(34)	(21)
Net Amount	111	119
Interest rate swaps
Derivative Assets
Gross Amounts of Recognized Assets	16	0
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	16	0
Derivative Asset, Not Offset, Policy Election Deduction	(2)	0
Cash Collateral Received	0	0
Net Amount	14	0
Foreign exchange forwards
Derivative Assets
Gross Amounts of Recognized Assets	175	215
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	175	215
Derivative Asset, Not Offset, Policy Election Deduction	(48)	(76)
Cash Collateral Received	(31)	(21)
Net Amount	96	118
Client foreign currency options
Derivative Assets
Gross Amounts of Recognized Assets	2	2
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	2	2
Derivative Asset, Not Offset, Policy Election Deduction	(1)	(1)
Cash Collateral Received	0	0
Net Amount	1	1
Client interest rate derivatives
Derivative Assets
Gross Amounts of Recognized Assets	65	68
Gross Amounts offset in the Statement of Financial Position	0	0
Net Amounts of Assets Presented in the Statement of Financial Position	65	68
Derivative Asset, Not Offset, Policy Election Deduction	(62)	(68)
Cash Collateral Received	(3)	0
Net Amount	$ 0	$ 0