Fair value measurement - Assets on Nonrecurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets	$ 1,268	$ 1,187
Measured at fair value on a nonrecurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	37	42
Other assets	426	265
Total assets	463	307
Measured at fair value on a nonrecurring basis | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Other assets	0	0
Total assets	0	0
Measured at fair value on a nonrecurring basis | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	37	42
Other assets	426	265
Total assets	463	307
Measured at fair value on a nonrecurring basis | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans	0	0
Other assets	0	0
Total assets	$ 0	$ 0