Leases (Textuals) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Operating liability, current	$ 60	$ 60			$ 0
Operating liability, noncurrent	184	184
Right-of-use assets	247	247		$ 267
Revenue from lease arrangements	65	188
Assets subject to rental	262	262
Assets subject to rental, accumulated amortization	171	171
Lessor, Lease, Description [Line Items]
Depreciation		88	$ 87
Leased Assets
Lessor, Lease, Description [Line Items]
Depreciation	$ 7	$ 21