Leases Leases - Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Assets and Liabilities, Lessee [Abstract]
Total lease assets	$ 267
Operating lease liability	243	$ 278
Finance lease liability	57
Total lease liabilities	300
Other assets [Member]
Assets and Liabilities, Lessee [Abstract]
Operating lease assets	215
Finance lease assets	52
Other liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Operating lease liability	243
Long-term debt [Member]
Assets and Liabilities, Lessee [Abstract]
Finance lease liability	$ 57