Segment Information (Financial Information by Segment) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) region	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) region	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information
Revenues	$ 2,488	$ 2,116	$ 6,895	$ 5,741
Depreciation and amortization expense	519	418	1,522	1,201
Equipment rentals gross profit	1,033	938	2,705	2,366
Capital expenditures			2,131	2,096
Assets	19,405		19,405		$ 18,133
Equipment rentals
Segment Reporting Information
Revenues	2,147	1,861	5,902	4,951
Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	198	140	587	478
Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	67	54	189	140
Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	27	24	78	66
Service and other revenues
Segment Reporting Information
Revenue from contract with customer	49	37	139	106
Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 917	847	$ 2,367	2,080
General rentals
Segment Reporting Information
Number of geographic regions entity operates in (locations) | region	11		11
Revenues	$ 1,944	1,674	$ 5,472	4,693
Depreciation and amortization expense	426	351	1,254	1,022
Capital expenditures			1,800	1,845
Assets	16,383		16,383		15,597
General rentals | Equipment rentals
Segment Reporting Information
Revenues	1,642	1,444	4,592	3,977
General rentals | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	183	130	541	446
General rentals | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	60	50	167	125
General rentals | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	17	17	53	50
General rentals | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	42	33	119	95
General rentals | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	671	629	1,765	1,598
Trench, power and fluid solutions
Segment Reporting Information
Revenues	544	442	1,423	1,048
Depreciation and amortization expense	93	67	268	179
Capital expenditures			331	251
Assets	3,022		3,022		$ 2,536
Trench, power and fluid solutions | Equipment rentals
Segment Reporting Information
Revenues	505	417	1,310	974
Trench, power and fluid solutions | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	15	10	46	32
Trench, power and fluid solutions | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	7	4	22	15
Trench, power and fluid solutions | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	10	7	25	16
Trench, power and fluid solutions | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	7	4	20	11
Trench, power and fluid solutions | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 246	$ 218	$ 602	$ 482