Variable interest entities - Non-consolidated VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Assets	$ 427,953	$ 444,438
Liabilities	388,057	401,047
Securities – Available-for-sale | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	152	189
Liabilities	0	0
Maximum loss exposure	152	189
Other | Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	2,323	2,385
Liabilities	595	543
Maximum loss exposure	$ 2,932	$ 2,946