Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Details) - USD ($) $ in Millions		Dec. 31, 2022		Dec. 31, 2021		Dec. 31, 2020	[1]	Dec. 31, 2019	[1]
Financial Assets:
Cash and cash equivalents, Carrying Value		$ 2,032		$ 2,211	[1]	$ 1,948		$ 742
Cash and cash equivalents, Estimated Fair Value		2,032		2,211
FHLB and FRB stock, Carrying Value	[2]	1,267
FHLB and FRB stock, Estimated Fair Value	[2]	1,267
FHLB stock, Carrying Value		1,267		734	[2]
FHLB stock, Estimated Fair Value	[2]			734
Loans and leases, net, Carrying Value		68,608		45,539
Loans and leases, net, Estimated Fair Value		65,673		44,748
Financial Liabilities:
Deposits, Carrying Value		58,721		35,059
Deposits, Estimated Fair Value		58,479		35,051
Borrowed funds, Carrying Value		21,332		16,562
Borrowed funds, Estimated Fair Value		21,231		17,169
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets:
Cash and cash equivalents, Carrying Value		2,032		2,211
Financial Liabilities:
Deposits, Carrying Value		46,211	[3]	26,635	[4]
Significant Other Observable Inputs (Level 2)
Financial Assets:
FHLB and FRB stock, Carrying Value	[5]	1,267
FHLB stock, Carrying Value	[2]			734
Financial Liabilities:
Deposits, Carrying Value		12,268	[6]	8,416	[7]
Borrowed funds, Carrying Value		21,231		17,169
Significant Unobservable Inputs (Level 3)
Financial Assets:
Loans and leases, net, Carrying Value		$ 65,673		$ 44,748

[1] For further information on restricted cash, see Note 14 - Derivatives and Hedging Activities.

[2] Carrying value and estimated fair value are at cost.

[3] Interest-bearing checking and money market accounts, savings accounts, and non-interest-bearing accounts.

[4] Interest-bearing checking and money market accounts, savings accounts, and non-interest-bearing accounts.

[5] Carrying value and estimated fair value are at cost.

[6] Certificates of deposit.

[7] Certificates of deposit.