Segment Information (Geographic area information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Equipment rentals									$ 4,941	$ 4,949	$ 4,819
Sales of rental equipment									496	538	544
Sales of new equipment									144	157	149
Contractor supplies sales									79	79	85
Service and other revenues									102	94	88
Total revenues	$ 1,523	$ 1,508	$ 1,421	$ 1,310	$ 1,523	$ 1,550	$ 1,429	$ 1,315	5,762	5,817	5,685
Goodwill and other intangibles, net	4,002				4,148				4,002	4,148
Domestic
Revenues from External Customers and Long-Lived Assets [Line Items]
Equipment rentals									4,524	4,452	4,217
Sales of rental equipment									444	480	478
Sales of new equipment									129	137	124
Contractor supplies sales									68	69	70
Service and other revenues									87	80	73
Total revenues									5,252	5,218	4,962
Goodwill and other intangibles, net	3,699				3,838				3,699	3,838
Foreign (Canada)
Revenues from External Customers and Long-Lived Assets [Line Items]
Equipment rentals									417	497	602
Sales of rental equipment									52	58	66
Sales of new equipment									15	20	25
Contractor supplies sales									11	10	15
Service and other revenues									15	14	15
Total revenues									510	599	$ 723
Goodwill and other intangibles, net	303				310				303	310
Rental equipment, net
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	6,189				6,186				6,189	6,186
Rental equipment, net | Domestic
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	5,709				5,657				5,709	5,657
Rental equipment, net | Foreign (Canada)
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	480				529				480	529
Property and equipment, net
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	430				445				430	445
Property and equipment, net | Domestic
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	390				399				390	399
Property and equipment, net | Foreign (Canada)
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 40				$ 46				$ 40	$ 46