Leases (Supplemental Balance Sheet Information Related to Leases) (Details) - USD ($) $ in Millions		Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating lease, right-of-use asset		$ 459	$ 434
Total leased assets		554	537
Operating lease, liability, noncurrent		315	304
Lease liability total		558	538
Other Accrued Liabilities [Member]
Leases [Abstract]
Finance lease, liability, current		13	12
Finance lease, liability, current		13	12
Property, Plant and Equipment [Member]
Leases [Abstract]
Finance lease, right-of-use asset	[1]	95	103
Finance lease, right-of-use asset	[1]	95	103
Other (c)
Leases [Abstract]
Finance lease, liability, noncurrent		82	88
Finance lease, liability, noncurrent		82	88
Short-term Debt [Member]
Leases [Abstract]
Operating lease, liability, current		148	134
Operating lease, liability, current		$ 148	$ 134

[1] Finance leases are recorded net of accumulated amortization of $53 million and $40 million at December 31, 2020 and 2019, respectively.