New Accounting Standards (Narrative) (Details) $ in Millions	Mar. 31, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease ROU asset	$ 197
Operating lease liability	204
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease ROU asset	207
Operating lease liability	$ 214