Segment Reporting - Net Revenues by Product Category (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net revenues	$ 6,913	$ 6,355	$ 6,062	$ 6,538	$ 6,773	$ 6,288	$ 6,112	$ 6,765	$ 25,868	$ 25,938	$ 25,896
Biscuits
Segment Reporting Information [Line Items]
Net revenues									11,438	11,185	10,839
Chocolate
Segment Reporting Information [Line Items]
Net revenues									8,158	8,177	8,032
Gum & Candy
Segment Reporting Information [Line Items]
Net revenues									3,355	3,491	3,638
Beverages
Segment Reporting Information [Line Items]
Net revenues									1,095	1,184	1,355
Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues									1,822	1,901	2,032
Latin America
Segment Reporting Information [Line Items]
Net revenues									3,018	3,202	3,566
Latin America | Biscuits
Segment Reporting Information [Line Items]
Net revenues									708	727	779
Latin America | Chocolate
Segment Reporting Information [Line Items]
Net revenues									710	747	862
Latin America | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues									823	865	919
Latin America | Beverages
Segment Reporting Information [Line Items]
Net revenues									452	533	665
Latin America | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues									325	330	341
AMEA
Segment Reporting Information [Line Items]
Net revenues									5,770	5,729	5,739
AMEA | Biscuits
Segment Reporting Information [Line Items]
Net revenues									1,844	1,724	1,637
AMEA | Chocolate
Segment Reporting Information [Line Items]
Net revenues									2,082	2,080	2,008
AMEA | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues									861	879	919
AMEA | Beverages
Segment Reporting Information [Line Items]
Net revenues									546	553	569
AMEA | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues									437	493	606
Europe
Segment Reporting Information [Line Items]
Net revenues									9,972	10,122	9,794
Europe | Biscuits
Segment Reporting Information [Line Items]
Net revenues									2,998	3,127	2,944
Europe | Chocolate
Segment Reporting Information [Line Items]
Net revenues									5,119	5,083	4,869
Europe | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues									698	736	775
Europe | Beverages
Segment Reporting Information [Line Items]
Net revenues									97	98	121
Europe | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues									1,060	1,078	1,085
North America
Segment Reporting Information [Line Items]
Net revenues									7,108	6,885	6,797
North America | Biscuits
Segment Reporting Information [Line Items]
Net revenues									5,888	5,607	5,479
North America | Chocolate
Segment Reporting Information [Line Items]
Net revenues									247	267	293
North America | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues									973	1,011	1,025
North America | Beverages
Segment Reporting Information [Line Items]
Net revenues									0	0	0
North America | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues									$ 0	$ 0	$ 0