Leases - Supplemental information (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Supplemental balance sheet information
Balance sheet location for assets	us-gaap:OtherAssetsMember
Operating lease right-of-use assets	$ 380	$ 302
Balance sheet location for current liabilities	us-gaap:OtherCurrentLiabilitiesMember
Current operating lease liabilities	$ 73	63
Balance sheet location for non-current liabilities	us-gaap:OtherLiabilitiesMember
Noncurrent operating lease liabilities	$ 301	232
Finance lease ROU assets, net	$ 10	11
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet
Finance Lease, Liability, Current	$ 2	2
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Short Term Borrowings and Long Term debt, Current
Finance Lease, Liability, Noncurrent	$ 9	$ 10
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtNoncurrent