Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Contract assets	$ 166	$ 162
Contract liabilities	2,944	2,301
Contract liabilities, current	2,213	1,769
Contract liabilities in other long-term liabilities	731	$ 532
Revenue recognized	1,017
Estimated consideration related to unsatisfied performance obligations	$ 54,000
Long-term supply contracts	20 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Disaggregation of Revenue [Line Items]
Remaining performance obligations, period	5 years
Remaining performance obligation, percentage	50.00%
Minimum
Disaggregation of Revenue [Line Items]
On-site product supply contract	10 years
Minimum | Merchant
Disaggregation of Revenue [Line Items]
Customer supply agreements	3 years
Minimum | Packaged Gas
Disaggregation of Revenue [Line Items]
Customer supply agreements	1 year
Maximum
Disaggregation of Revenue [Line Items]
On-site product supply contract	20 years
Maximum | Merchant
Disaggregation of Revenue [Line Items]
Customer supply agreements	7 years
Maximum | Packaged Gas
Disaggregation of Revenue [Line Items]
Customer supply agreements	3 years