Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Assets:
Investments	$ 10	$ 11
Foreign Exchange Contracts	18	4
Total Assets at Fair Value	28	15
Liabilities:
Foreign Exchange Contracts	7	19
Total Liabilities at Fair Value	7	19
Supplemental Fair Value Information
Carrying amount — liability	5,316	5,427
Notes payable and overdrafts	410	262
Fixed Rate Debt, Excluding Capital Leases
Supplemental Fair Value Information
Carrying amount — liability	3,609	3,616
Fair value — liability	3,443	3,786
Notes payable and overdrafts	230	110
Variable Rate Debt, Excluding Capital Leases
Supplemental Fair Value Information
Carrying amount — liability	1,707	1,811
Fair value — liability	1,689	1,811
Notes payable and overdrafts	180	152
Quoted Prices in Active Markets for Identical Assets/Liabilities (Level 1)
Assets:
Investments	10	11
Foreign Exchange Contracts	0	0
Total Assets at Fair Value	10	11
Liabilities:
Foreign Exchange Contracts	0	0
Total Liabilities at Fair Value	0	0
Supplemental Fair Value Information
Fair value — liability	3,496	3,857
Significant Other Observable Inputs (Level 2)
Assets:
Investments	0	0
Foreign Exchange Contracts	18	4
Total Assets at Fair Value	18	4
Liabilities:
Foreign Exchange Contracts	7	19
Total Liabilities at Fair Value	7	19
Significant Unobservable Inputs (Level 3)
Assets:
Investments	0	0
Foreign Exchange Contracts	0	0
Total Assets at Fair Value	0	0
Liabilities:
Foreign Exchange Contracts	0	0
Total Liabilities at Fair Value	$ 0	$ 0