Recent Accounting Pronouncements Leases (ASU 2016-02) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating lease liability	$ 254	$ 243
Accounting Standards Update 2016-02 [Member]
Right-of-Use Asset			$ 274
Operating lease liability			$ 295