Leases (Textuals) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessor, Lease, Description [Line Items]
Operating liability, current	$ 63	$ 61
Operating liability, noncurrent	216	185
Right-of-use assets	272	241
Revenue from lease arrangements	195	247
Assets subject to rental	241	256
Assets subject to rental, accumulated amortization	159	166
Operating Leases, Rent Expense			$ 81
Depreciation	$ 117	$ 117	$ 117
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent	us-gaap:AccruedLiabilitiesCurrent
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherAccruedLiabilitiesNoncurrent	us-gaap:OtherAccruedLiabilitiesNoncurrent
Leased Assets
Lessor, Lease, Description [Line Items]
Depreciation	$ 25	$ 28