Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Tax at United States statutory rate					21.00%	21.00%	35.00%
Effective Income Tax Rate Reconciliation, Deduction, Dividend, Percent					100.00%
State income taxes, net of federal benefit					0.60%	1.00%	0.50%
Earnings taxed at other than United States statutory rate					4.70%	5.60%	(3.40%)
Charge for U.S. tax reform					0	0.023	0.079
Excess tax benefits from stock-based compensation					(0.20%)	(0.30%)	(1.40%)
Foreign Tax Credit Carryback					0.00%	(1.70%)	0.00%
(Benefit) charge for previously disclosed tax matters					(0.90%)	(0.40%)	0.00%
Foreign-derived intangible income benefit					(1.30%)	(1.10%)	0.00%
Other, net					(0.50%)	(0.20%)	(0.90%)
Effective tax rate					23.40%	26.20%	37.70%
Tax reform, provisional charge		$ 80		$ 275	$ 0	$ 80	$ 275
Tax benefit from exercise of stock options and vesting of restricted stock unit awards					6	12	$ 47
Income tax benefit related to changes in swiss preferential tax regime and increase to cantonal tax rate	$ 29
Benefit from foreign tax matter			$ 15			15
SWITZERLAND
Restructuring Cost and Reserve [Line Items]
Benefit from foreign tax matter	$ 29				$ 29	$ 15