Segment Information (Financial Information by Segment) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) region	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) region	Jun. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information
Revenues	$ 2,287	$ 1,939	$ 4,344	$ 4,064
Depreciation and amortization expense	475	490	941	1,016
Equipment rentals gross profit	875	701	1,589	1,428
Capital expenditures			1,261	455
Assets	19,641		19,641		$ 17,868
Equipment rentals
Segment Reporting Information
Revenues	1,951	1,642	3,618	3,425
Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	194	176	461	384
Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	57	53	106	115
Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	27	23	51	48
Service and other revenues
Segment Reporting Information
Revenue from contract with customer	58	45	108	92
Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 751	600	$ 1,328	1,210
General rentals
Segment Reporting Information
Number of geographic regions entity operates in (locations) | region	11		11
Revenues	$ 1,738	1,512	$ 3,360	3,206
Depreciation and amortization expense	392	401	772	838
Capital expenditures			1,116	377
Assets	15,587		15,587		15,051
General rentals | Equipment rentals
Segment Reporting Information
Revenues	1,466	1,255	2,739	2,649
General rentals | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	166	158	413	348
General rentals | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	38	45	80	98
General rentals | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	18	15	34	31
General rentals | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	50	39	94	80
General rentals | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	526	419	937	867
Specialty
Segment Reporting Information
Revenues	549	427	984	858
Depreciation and amortization expense	83	89	169	178
Capital expenditures			145	78
Assets	4,054		4,054		$ 2,817
Specialty | Equipment rentals
Segment Reporting Information
Revenues	485	387	879	776
Specialty | Sales of rental equipment
Segment Reporting Information
Revenue from contract with customer	28	18	48	36
Specialty | Sales of new equipment
Segment Reporting Information
Revenue from contract with customer	19	8	26	17
Specialty | Contractor supplies sales
Segment Reporting Information
Revenue from contract with customer	9	8	17	17
Specialty | Service and other revenues
Segment Reporting Information
Revenue from contract with customer	8	6	14	12
Specialty | Equipment rentals gross profit
Segment Reporting Information
Equipment rentals gross profit	$ 225	$ 181	$ 391	$ 343