Revenue Recognition (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Re-rent revenue, Topic 842	$ 41	$ 42	$ 105	$ 114
Ancillary and other rental revenues:
Revenues	2,187	2,488	6,251	6,895
Topic 842
Ancillary and other rental revenues:
Revenues	1,697	1,967	4,845	5,404
Topic 606
Ancillary and other rental revenues:
Revenues	490	521	1,406	1,491
Equipment rentals
Ancillary and other rental revenues:
Revenues	1,861	2,147	5,286	5,902
Equipment rentals | Topic 842
Ancillary and other rental revenues:
Revenues	1,697	1,967	4,845	5,404
Equipment rentals | Topic 606
Ancillary and other rental revenues:
Revenues	164	180	441	498
Owned equipment rentals
Revenues:
Owned equipment rentals, Topic 842	1,572	1,831	4,498	5,029
Owned equipment rentals | Topic 842
Revenues:
Owned equipment rentals, Topic 842	1,572	1,831	4,498	5,029
Re-rent revenue
Revenues:
Re-rent revenue, Topic 842	41	41	104	113
Re-rent revenue | Topic 842
Revenues:
Re-rent revenue, Topic 842	41	41	104	113
Ancillary and Other Rental Revenues
Revenues:
Revenue from contract with customer	138	156	370	418
Ancillary and other rental revenues:
Other	110	119	314	342
Revenues	248	275	684	760
Ancillary and Other Rental Revenues | Topic 842
Revenues:
Revenue from contract with customer	0	0	0	0
Ancillary and other rental revenues:
Other	84	95	243	262
Revenues	84	95	243	262
Ancillary and Other Rental Revenues | Topic 606
Revenues:
Revenue from contract with customer	138	156	370	418
Ancillary and other rental revenues:
Other	26	24	71	80
Revenues	164	180	441	498
Sales of rental equipment
Revenues:
Revenue from contract with customer	199	198	583	587
Sales of rental equipment | Topic 606
Revenues:
Revenue from contract with customer	199	198	583	587
Sales of new equipment
Revenues:
Revenue from contract with customer	54	67	169	189
Sales of new equipment | Topic 606
Revenues:
Revenue from contract with customer	54	67	169	189
Contractor supplies sales
Revenues:
Revenue from contract with customer	25	27	73	78
Contractor supplies sales | Topic 606
Revenues:
Revenue from contract with customer	25	27	73	78
Service and other revenues
Revenues:
Revenue from contract with customer	48	49	140	139
Service and other revenues | Topic 606
Revenues:
Revenue from contract with customer	$ 48	$ 49	$ 140	$ 139