Leases (Supplemental Information) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 47
Right-of-use assets obtained in exchange for operating liabilities:
Operating leases	95
Right-of-use asset balance:
Operating lease assets	159
Lease liability balance:
Current operating lease liabilities	34
Long-term operating lease liabilities	119
Total operating leases	$ 153
Operating Lease, Weighted Average Remaining Lease Term	6 years 7 months 6 days
Operating Lease, Weighted Average Discount Rate, Percent	5.33%