Segment Information (Financial Information by Segment) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 2,776	$ 2,596	$ 2,287	$ 2,057	$ 2,279	$ 2,187	$ 1,939	$ 2,125	$ 9,716	$ 8,530	$ 9,351
Revenue from contract with customer, excluding assessed tax									2,256	1,994	2,063
Depreciation and amortization									1,983	1,988	2,038
Equipment rentals gross profit	1,161	$ 1,103	$ 875	$ 714	869	$ 886	$ 701	$ 727	3,853	3,183	3,670
Capital expenditures									3,198	1,158	2,350
Total assets	20,292				17,868				20,292	17,868	18,970
Equipment rentals
Segment Reporting Information [Line Items]
Revenues									8,207	7,140	7,964
Revenue from contract with customer, excluding assessed tax									747	604	676
Sales of rental equipment
Segment Reporting Information [Line Items]
Revenues									968	858	831
Revenue from contract with customer, excluding assessed tax									968	858	831
Sales of new equipment
Segment Reporting Information [Line Items]
Revenues									203	247	268
Revenue from contract with customer, excluding assessed tax									203	247	268
Contractor supplies sales
Segment Reporting Information [Line Items]
Revenues									109	98	104
Revenue from contract with customer, excluding assessed tax									109	98	104
Service and other revenues
Segment Reporting Information [Line Items]
Revenues									229	187	184
Revenue from contract with customer, excluding assessed tax									229	187	184
Equipment rentals gross profit
Segment Reporting Information [Line Items]
Equipment rentals gross profit									3,267	2,719	3,207
General rentals
Segment Reporting Information [Line Items]
Revenues									7,351	6,699	7,436
Depreciation and amortization									1,611	1,633	1,681
Capital expenditures									2,719	969	1,967
Total assets	16,087				15,051				16,087	15,051	16,036
General rentals | Equipment rentals
Segment Reporting Information [Line Items]
Revenues									6,074	5,472	6,202
General rentals | Sales of rental equipment
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									862	785	768
General rentals | Sales of new equipment
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									142	214	238
General rentals | Contractor supplies sales
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									71	64	71
General rentals | Service and other revenues
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									202	164	157
General rentals | Equipment rentals gross profit
Segment Reporting Information [Line Items]
Equipment rentals gross profit									2,269	1,954	2,407
Specialty
Segment Reporting Information [Line Items]
Revenues									2,365	1,831	1,915
Depreciation and amortization									372	355	357
Capital expenditures									479	189	383
Total assets	$ 4,205				$ 2,817				4,205	2,817	2,934
Specialty | Equipment rentals
Segment Reporting Information [Line Items]
Revenues									2,133	1,668	1,762
Specialty | Sales of rental equipment
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									106	73	63
Specialty | Sales of new equipment
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									61	33	30
Specialty | Contractor supplies sales
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									38	34	33
Specialty | Service and other revenues
Segment Reporting Information [Line Items]
Revenue from contract with customer, excluding assessed tax									27	23	27
Specialty | Equipment rentals gross profit
Segment Reporting Information [Line Items]
Equipment rentals gross profit									$ 998	$ 765	$ 800