General Adoption of New Accounting Pronouncements (Details) - USD ($) $ in Millions	Jan. 01, 2019	Mar. 31, 2019
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
Operating Lease, Right-of-Use Asset		$ 608
Operating Lease, Liability		$ 653

Amount of the cumulative effect on retained earnings before related income tax effect.

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Amount of the cumulative effect on retained earnings net of related income tax effect.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Amount of lessee's right to use underlying asset under operating lease.

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