New Accounting Pronouncements (Details) - USD ($) $ in Millions		Jan. 01, 2019	Jun. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities			$ 786
Operating lease ROU assets	[1]		$ 735
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities		$ 780
Operating lease ROU assets		780
Increase in retained earnings, after tax		$ 27

[1] Reported net of level lease adjustments and exit cost obligations.