Commitments and contingent liabilities - Narrative (Details)							2 Months Ended	6 Months Ended
	Jun. 07, 2022 USD ($)	May 09, 2022 USD ($)	Aug. 04, 2021 investment_fund claim	May 20, 2021 USD ($)	Sep. 09, 2020 USD ($)	Dec. 17, 2015 lawsuit	Dec. 31, 2020 USD ($)	Jun. 30, 2022 USD ($) claim	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2009 claim
Commitments and Contingencies Disclosure [Line Items]
Lending commitment maturing in less than one year								$ 28,200,000,000
Lending commitment maturing in one to five years								20,000,000,000
Lending commitment maturing over five years								800,000,000
Allowance for credit losses on lending related commitments								$ 62,000,000	$ 53,000,000	$ 45,000,000	$ 50,000,000
Collateralization percentage generally required for a securities lending transaction with indemnification against broker default								102.00%
Securities lending indemnifications, secured amount of collateral								$ 516,000,000,000		511,000,000,000
Securities lending indemnifications, joint venture								67,000,000,000		67,000,000,000
Securities lending indemnifications, collateral joint venture								71,000,000,000		71,000,000,000
Unsettled Repurchase Agreements
Commitments and Contingencies Disclosure [Line Items]
Unsettled repurchase and reverse repurchase agreements								921,000,000		2,600,000,000
Unsettled Reverse Repurchase Agreements
Commitments and Contingencies Disclosure [Line Items]
Unsettled repurchase and reverse repurchase agreements								$ 4,100,000,000		9,100,000,000
Mortgage-Securitization Trusts Proceedings | Federal Court
Commitments and Contingencies Disclosure [Line Items]
Number of lawsuits or class actions (claim) | claim								3
Matters Related to R. Allen Stanford
Commitments and Contingencies Disclosure [Line Items]
Number of lawsuits or class actions (claim) | claim												2
New claims filed, number | claim								3
Brazilian Postalis Litigation
Commitments and Contingencies Disclosure [Line Items]
New claims filed, number			3			3
Damages awarded, value	$ 2,000,000	$ 20,000,000		$ 3,000,000	$ 50,000,000
Number of investment funds | investment_fund			3
Damages sought, value					$ 2,000,000
German Tax Matters | Foreign Tax Authority
Commitments and Contingencies Disclosure [Line Items]
Damages sought, value							$ 150,000,000
Maximum
Commitments and Contingencies Disclosure [Line Items]
Loss contingency, aggregate range of reasonable loss (up to)								$ 550,000,000
Standby letters of credit
Commitments and Contingencies Disclosure [Line Items]
Standby letters of credit (SBLC) collateralized with cash and securities								162,000,000		172,000,000
SBLC expiring within one year								1,300,000,000
SBLC expiring within one to five years								736,000,000
SBLC expiring over five years								0
Off-balance sheet credit risks								2,029,000,000		1,971,000,000
Commercial letters of credit
Commitments and Contingencies Disclosure [Line Items]
Off-balance sheet credit risks								$ 144,000,000		$ 56,000,000