Background - Basis of Presentation (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease, right-of-use asset, Statement of Financial Position [Extensible Enumeration]	Other, net	Other, net
Current operating lease liabilities	$ 283	$ 241
Operating lease liabilities	942	903
Affiliates
Lessee, Lease, Description [Line Items]
Operating lease assets	243	83
Current operating lease liabilities	67	31
Operating lease liabilities	$ 187	$ 65