Leasing (Lessee, Operating Lease, Liability, Maturity) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Leases [Abstract]
2020	$ 25
2021	43
2022	30
2023	20
2024	13
2025 and thereafter	46
Total undiscounted cash flows	177
Difference between undiscounted cash flows and discounted cash flows	(14)
Operating lease, liabilities	163	$ 196
Purchases Of Operating Lease Assets	48
Lessee, Operating Lease, Lease Not yet Commenced, Undiscounted Future Lease Payments	$ 290
Lessee, Operating Lease, Lease Not yet Commenced, Term of Contract	15 years