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Revenue Recognition (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred revenue	$ 51	$ 55
Accounts receivable, net	1,315	1,530
Accounts receivable, allowance for doubtful accounts	108	103
Provision for doubtful accounts	9
Contract with customer, asset, after allowance for credit loss	0
Contract with customer, liability, revenue recognized	0	0
Contract with customer, performance obligation satisfied in previous period	$ 0	$ 0
Product concentration risk \| Revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	84.00%
Customer concentration risk \| Revenues \| Largest customer
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	1.00%	1.00%	1.00%
Customer concentration risk \| Accounts receivable
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	2.00%	1.00%
Owned Equipment Rentals \| Product concentration risk \| Revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	71.00%
Total equipment rentals \| Product concentration risk \| Revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	77.00%
General rentals \| Product concentration risk \| Revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	79.00%
UNITED STATES \| Geographic Concentration Risk \| Revenues
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage	91.00%