Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Non-Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2022		Dec. 31, 2021		Dec. 31, 2020
Financial Assets:
Cash and cash equivalents, and due from banks, Carrying Value	$ 1,700		$ 2,211		$ 1,948
Cash and cash equivalents and due from banks, Estimated Fair Value	1,700		2,211
FHLB stock, Carrying Value	630	[1]	734	[2]
FHLB stock, Estimated Fair Value	630	[1]	734	[2]
Loans and leases, net, Carrying Value	48,766		45,539
Loans and leases, net, Estimated Fair Value	45,725		44,748
Financial Liabilities:
Deposits, Carrying Value	41,705		35,059
Deposits, Estimated Fair Value	41,448		35,051
Borrowed funds, Carrying Value	13,798		16,562
Borrowed funds, Estimated Fair Value	13,615		17,169
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets:
Cash and cash equivalents, and due from banks, Carrying Value	1,700		2,211
Financial Liabilities:
Deposits, Carrying Value	32,596	[3]	26,635	[4]
Significant Other Observable Inputs (Level 2)
Financial Assets:
FHLB stock, Carrying Value	630	[1]	734	[2]
Financial Liabilities:
Deposits, Carrying Value	8,852	[5]	8,416	[6]
Borrowed funds, Carrying Value	13,615		17,169
Significant Unobservable Inputs (Level 3)
Financial Assets:
Loans and leases, net, Carrying Value	$ 45,725		$ 44,748

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

[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] Certificates of deposit.

[6] Certificates of deposit.