Divestiture and held for sale - Narrative (Details) - USD ($)			3 Months Ended	9 Months Ended
	Aug. 10, 2020	Feb. 03, 2020	Sep. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets impairment charge				$ 0	$ 168,000,000
Proceeds from divestitures				$ 0	198,000,000
Disposal Group, Held-for-sale, Not Discontinued Operations | VBS
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets impairment charge					$ 144,000,000
Disposal group, including discontinued operation, consideration	$ 1
Proceeds from divestitures	$ 22,000,000
Disposal group, not discontinued operation, gain (loss) on disposal, net			$ 0
Disposal Group, Held-for-sale, Not Discontinued Operations | VBNS
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, including discontinued operation, consideration		$ 176,000,000
Disposal group, not discontinued operation, gain (loss) on disposal, net		175,000,000
Disposal group, not discontinued operation, gain (loss) on disposal, net of closing costs		$ 77,000,000