Income Taxes - Tax Rate Analysis (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S. statutory income tax	$ 1,060	$ 801	$ 717
U.S. statutory income tax rate percentage	21.00%	35.00%	35.00%
State and local taxes – net of federal benefit	$ 30	$ 32	$ 28
State and local taxes - net of federal benefit percentage	0.60%	1.40%	1.40%
U.S. tax credits and deductions	$ (12)	$ (27)	$ (32)
U.S. tax credits and deductions percentage	(0.20%)	(1.20%)	(1.60%)
Foreign tax differentials	$ 57	$ (145)	$ (140)
Foreign tax rate differentials percentage	1.10%	(6.30%)	(6.80%)
Share Based Compensation	$ (22)	$ (35)	$ (20)
Share Based Compensation - percentage	(0.40%)	(1.50%)	(1.00%)
Tax Act	$ (61)	$ 394	$ 0
Tax Act - percentage	(1.20%)	17.20%	0.00%
Divestitures	$ (321)	$ 0	$ 0
Divestitures - net percentage	(6.40%)	0.00%	0.00%
Other – net	$ 86	$ 6	$ (2)
Other - net percentage	1.70%	0.30%	(0.10%)
Income Tax Expense (Benefit)	$ 817	$ 1,026	$ 551
Provision for income taxes percentage	16.20%	44.90%	26.90%
U.S. tax related GILTI	$ 34
Unrecognized tax benefits, in Europe	$ 44