Basis of Presentation and Accounting Policies - Recently Issued Accounting Pronouncements (Narrative) (Details) - Subsequent Event $ in Millions	Oct. 01, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification of tax effects from accumulated other comprehensive loss into retained earnings	$ 147
Accounting Standards Update 2016-02 [Member] | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right of use asset	335
Operating lease, liability	335
Accounting Standards Update 2016-02 [Member] | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, right of use asset	305
Operating lease, liability	$ 305