Segment Information (Financial Information by Segment) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) region	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) region	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information
Revenues	$ 2,187	$ 2,488	$ 6,251	$ 6,895
Depreciation and amortization expense	492	519	1,508	1,522
Equipment rentals gross profit	886	1,033	2,314	2,705
Capital expenditures			930	2,131
Assets	17,908		17,908		$ 18,970
Equipment rentals
Segment Reporting Information
Revenues	1,861	2,147	5,286	5,902
Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	199	198	583	587
Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	54	67	169	189
Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	25	27	73	78
Service and other revenues
Segment Reporting Information
Revenue from contract with customer	48	49	140	139
Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 777	917	$ 1,987	2,367
General rentals
Segment Reporting Information
Number of geographic regions entity operates in (locations) | region	11		11
Revenues	$ 1,679	1,944	$ 4,885	5,472
Depreciation and amortization expense	402	426	1,240	1,254
Capital expenditures			771	1,800
Assets	15,039		15,039		16,036
General rentals | Equipment rentals
Segment Reporting Information
Revenues	1,391	1,642	4,040	4,592
General rentals | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	182	183	530	541
General rentals | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	47	60	145	167
General rentals | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	17	17	48	53
General rentals | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	42	42	122	119
General rentals | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	543	671	1,410	1,765
Trench, power and fluid solutions
Segment Reporting Information
Revenues	508	544	1,366	1,423
Depreciation and amortization expense	90	93	268	268
Capital expenditures			159	331
Assets	2,869		2,869		$ 2,934
Trench, power and fluid solutions | Equipment rentals
Segment Reporting Information
Revenues	470	505	1,246	1,310
Trench, power and fluid solutions | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	17	15	53	46
Trench, power and fluid solutions | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	7	7	24	22
Trench, power and fluid solutions | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	8	10	25	25
Trench, power and fluid solutions | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	6	7	18	20
Trench, power and fluid solutions | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 234	$ 246	$ 577	$ 602