Loans and Allowance for Credit Losses - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) security loan loanSegment	Dec. 31, 2023 USD ($) security loan	Dec. 31, 2022 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Percentage of investment portfolio considered investment grade	99.00%
Marketable securities, unrealized gain (loss)	$ 6,120	$ 6,190
Number of securities in loss position | security	1,564	1,704
Number of loans and leases segments | loanSegment	2
Financing receivable, excluding accrued interest, after allowance for credit loss	$ 43,026	$ 36,496
Number of loans on non-accrual status | loan	2	3
Financing receivable, nonaccrual	$ 191	$ 70
Sale of loans	246	506	$ 1,786
Provision for credit losses	$ 75	46	$ 20
Investment grade loans	88.00%
Speculative grade loans	11.00%
Speculative senior secured loans with BB or B rating	91.00%
Non-accrual status, more than 90 days
Financing Receivable, Credit Quality Indicator [Line Items]
Number of loans on non-accrual status | loan	1
Financing receivable, nonaccrual	$ 101
Asset Pledged as Collateral
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, excluding accrued interest, after allowance for credit loss	13,900	$ 13,000
Leveraged loans
Financing Receivable, Credit Quality Indicator [Line Items]
Sale of loans	300
Provision for credit losses	$ (37)
Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans no longer meeting similar risk of collective pool | loan	4
Loans no longer meeting similar risk of collective pool, amount	$ 48
Allowance for credit loss	91
Collateralized loan obligations in loan form
Financing Receivable, Credit Quality Indicator [Line Items]
Payments to acquire loans receivable	$ 3,720
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans no longer meeting similar risk of collective pool | loan	5
Loans no longer meeting similar risk of collective pool, amount	$ 402