General Adoption of New Accounting Pronouncements (Details) - USD ($) $ in Millions |
Jan. 01, 2019 |
Sep. 30, 2019 |
---|---|---|
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
Operating Lease, Right-of-Use Asset | $ 577 | |
Operating Lease, Liability | $ 617 | |
Accounting Standards Update 2017-08 [Member] | ||
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
Cumulative Effect on Retained Earnings, Net of Tax | $ 12 | |
Cumulative Effect on Retained Earnings, before Tax | 15 | |
Accounting Standards Update 2016-02 [Member] | ||
New Accounting Pronouncements or Change in Accounting Principle [Line Items] | ||
Cumulative Effect on Retained Earnings, before Tax | $ 0 |