Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Currently payable
Federal	$ 698	$ 1,022	$ 1,192
State	109	59	75
International	763	722	733
Tax Cuts and Jobs Act (TCJA) non-current transition tax provision	176	623
Deferred
Federal	(38)	162	(3)
State	(17)	15	9
International	(54)	76	(11)
Total provision for income taxes	$ 1,637	$ 2,679	$ 1,995

The noncurrent transition tax provision specific to the Tax Cuts and Jobs Act of 2017.

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