Contract revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Capitalized Contract Cost [Line Items]
Contract with customer, asset	$ 2,500			$ 2,500		$ 2,500
Contract assets representing accrued revenues not yet billed	68			68		42
Contract with customer, liability	182			182		163
Contract with customer, liability, revenue recognized	71			106
Incremental costs for obtaining contracts
Capitalized Contract Cost [Line Items]
Capitalized contract costs	$ 57			$ 57		64
Capitalized contract cost, amortization period	9 years			9 years
Capitalized contract cost, amortization	$ 5	$ 4	$ 5	$ 14	$ 15
Costs to fulfill contract
Capitalized Contract Cost [Line Items]
Capitalized contract costs	25			25		$ 23
Capitalized contract cost, amortization	$ 1	$ 1	$ 1	$ 1	$ 1
Costs to fulfill contract | Minimum
Capitalized Contract Cost [Line Items]
Capitalized contract cost, amortization period	7 years			7 years
Costs to fulfill contract | Maximum
Capitalized Contract Cost [Line Items]
Capitalized contract cost, amortization period	9 years			9 years