Revenue Recognition - Schedule of Revenue by Distribution Method (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Total segment sales	$ 7,668	$ 6,855	$ 22,495	$ 19,971
Americas
Disaggregation of Revenue [Line Items]
Total segment sales	3,091	2,641	8,951	7,735
EMEA
Disaggregation of Revenue [Line Items]
Total segment sales	1,911	1,622	5,585	4,703
APAC
Disaggregation of Revenue [Line Items]
Total segment sales	1,564	1,484	4,544	4,115
Engineering
Disaggregation of Revenue [Line Items]
Total segment sales	601	678	1,921	2,096
Other
Disaggregation of Revenue [Line Items]
Total segment sales	501	430	1,494	1,322
Merchant
Disaggregation of Revenue [Line Items]
Total segment sales	2,009	1,771	5,818	5,010
Merchant | Americas
Disaggregation of Revenue [Line Items]
Total segment sales	849	739	2,441	2,099
Merchant | EMEA
Disaggregation of Revenue [Line Items]
Total segment sales	559	472	1,646	1,357
Merchant | APAC
Disaggregation of Revenue [Line Items]
Total segment sales	563	526	1,598	1,444
Merchant | Engineering
Disaggregation of Revenue [Line Items]
Total segment sales	0	0	0	0
Merchant | Other
Disaggregation of Revenue [Line Items]
Total segment sales	38	34	133	110
On-Site
Disaggregation of Revenue [Line Items]
Total segment sales	1,876	1,484	5,261	4,298
On-Site | Americas
Disaggregation of Revenue [Line Items]
Total segment sales	836	622	2,299	1,831
On-Site | EMEA
Disaggregation of Revenue [Line Items]
Total segment sales	462	334	1,250	981
On-Site | APAC
Disaggregation of Revenue [Line Items]
Total segment sales	578	528	1,712	1,486
On-Site | Engineering
Disaggregation of Revenue [Line Items]
Total segment sales	0	0	0	0
On-Site | Other
Disaggregation of Revenue [Line Items]
Total segment sales	0	0	0	0
Packaged Gas
Disaggregation of Revenue [Line Items]
Total segment sales	2,666	2,482	7,904	7,230
Packaged Gas | Americas
Disaggregation of Revenue [Line Items]
Total segment sales	1,385	1,265	4,086	3,750
Packaged Gas | EMEA
Disaggregation of Revenue [Line Items]
Total segment sales	880	799	2,652	2,329
Packaged Gas | APAC
Disaggregation of Revenue [Line Items]
Total segment sales	394	413	1,147	1,135
Packaged Gas | Engineering
Disaggregation of Revenue [Line Items]
Total segment sales	0	0	0	0
Packaged Gas | Other
Disaggregation of Revenue [Line Items]
Total segment sales	7	5	19	16
Other
Disaggregation of Revenue [Line Items]
Total segment sales	1,117	1,118	3,512	3,433
Other | Americas
Disaggregation of Revenue [Line Items]
Total segment sales	21	15	125	55
Other | EMEA
Disaggregation of Revenue [Line Items]
Total segment sales	10	17	37	36
Other | APAC
Disaggregation of Revenue [Line Items]
Total segment sales	29	17	87	50
Other | Engineering
Disaggregation of Revenue [Line Items]
Total segment sales	601	678	1,921	2,096
Other | Other
Disaggregation of Revenue [Line Items]
Total segment sales	$ 456	$ 391	$ 1,342	$ 1,196
Revenue from Contract with Customer | Sales Channel
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Revenue from Contract with Customer | Sales Channel | Merchant
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	26.00%	26.00%	26.00%	25.00%
Revenue from Contract with Customer | Sales Channel | On-Site
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	24.00%	22.00%	23.00%	22.00%
Revenue from Contract with Customer | Sales Channel | Packaged Gas
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	35.00%	36.00%	35.00%	36.00%
Revenue from Contract with Customer | Sales Channel | Other
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	15.00%	16.00%	16.00%	17.00%