Segment Reporting - Net Revenues by Product Category (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net revenues	$ 5,911	$ 6,062	$ 12,618	$ 12,600
Biscuits
Segment Reporting Information [Line Items]
Net revenues	3,110	2,809	6,136	5,546
Chocolate
Segment Reporting Information [Line Items]
Net revenues	1,520	1,643	3,676	3,849
Gum & Candy
Segment Reporting Information [Line Items]
Net revenues	535	847	1,316	1,660
Beverages
Segment Reporting Information [Line Items]
Net revenues	267	297	565	618
Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues	479	466	925	927
Latin America
Segment Reporting Information [Line Items]
Net revenues	511	737	1,237	1,537
Latin America | Biscuits
Segment Reporting Information [Line Items]
Net revenues	154	186	328	356
Latin America | Chocolate
Segment Reporting Information [Line Items]
Net revenues	119	157	313	387
Latin America | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues	65	209	247	409
Latin America | Beverages
Segment Reporting Information [Line Items]
Net revenues	90	108	192	231
Latin America | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues	83	77	157	154
AMEA
Segment Reporting Information [Line Items]
Net revenues	1,237	1,352	2,739	2,893
AMEA | Biscuits
Segment Reporting Information [Line Items]
Net revenues	458	405	966	866
AMEA | Chocolate
Segment Reporting Information [Line Items]
Net revenues	361	438	904	995
AMEA | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues	153	224	338	449
AMEA | Beverages
Segment Reporting Information [Line Items]
Net revenues	157	169	328	341
AMEA | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues	108	116	203	242
Europe
Segment Reporting Information [Line Items]
Net revenues	2,138	2,247	4,722	4,798
Europe | Biscuits
Segment Reporting Information [Line Items]
Net revenues	694	767	1,440	1,501
Europe | Chocolate
Segment Reporting Information [Line Items]
Net revenues	1,001	1,006	2,364	2,366
Europe | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues	135	181	308	354
Europe | Beverages
Segment Reporting Information [Line Items]
Net revenues	20	20	45	46
Europe | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues	288	273	565	531
North America
Segment Reporting Information [Line Items]
Net revenues	2,025	1,726	3,920	3,372
North America | Biscuits
Segment Reporting Information [Line Items]
Net revenues	1,804	1,451	3,402	2,823
North America | Chocolate
Segment Reporting Information [Line Items]
Net revenues	39	42	95	101
North America | Gum & Candy
Segment Reporting Information [Line Items]
Net revenues	182	233	423	448
North America | Beverages
Segment Reporting Information [Line Items]
Net revenues	0	0	0	0
North America | Cheese & Grocery
Segment Reporting Information [Line Items]
Net revenues	$ 0	$ 0	$ 0	$ 0