Segment Information (Financial Information by Segment) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($) region	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) region	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information
Revenues	$ 2,290	$ 1,891	$ 4,407	$ 3,625
Depreciation and amortization expense	504	390	1,003	783
Equipment rentals gross profit	911	782	1,672	1,428
Capital expenditures			1,226	1,306
Assets	19,047		19,047		$ 18,133
Equipment rentals
Segment Reporting Information
Revenues	1,960	1,631	3,755	3,090
Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	197	157	389	338
Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	60	44	122	86
Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	27	24	51	42
Service and other revenues
Segment Reporting Information
Revenue from contract with customer	46	35	90	69
Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 792	688	$ 1,450	1,233
General rentals
Segment Reporting Information
Number of geographic regions entity operates in (locations) | region	11		11
Revenues	$ 1,818	1,566	$ 3,528	3,019
Depreciation and amortization expense	416	334	828	671
Capital expenditures			1,015	1,153
Assets	16,124		16,124		15,597
General rentals | Equipment rentals
Segment Reporting Information
Revenues	1,527	1,332	2,950	2,533
General rentals | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	180	145	358	316
General rentals | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	52	38	107	75
General rentals | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	19	19	36	33
General rentals | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	40	32	77	62
General rentals | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	593	543	1,094	969
Trench, power and fluid solutions
Segment Reporting Information
Revenues	472	325	879	606
Depreciation and amortization expense	88	56	175	112
Capital expenditures			211	153
Assets	2,923		2,923		$ 2,536
Trench, power and fluid solutions | Equipment rentals
Segment Reporting Information
Revenues	433	299	805	557
Trench, power and fluid solutions | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	17	12	31	22
Trench, power and fluid solutions | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	8	6	15	11
Trench, power and fluid solutions | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	8	5	15	9
Trench, power and fluid solutions | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	6	3	13	7
Trench, power and fluid solutions | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 199	$ 145	$ 356	$ 264