Acquisitions (Intangibles) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended		12 Months Ended
	Apr. 30, 2014		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill			$ 3,272	[1]	$ 2,953	[1]	$ 2,970	[1]	$ 289	[1]
National Pump
Acquired Finite-Lived Intangible Assets [Line Items]
Fair value	289
Goodwill	333	[2]
Goodwill expected to be deductible for tax purposes	348
National Pump | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Fair value	274		236
Life (years)	10 years		10 years
National Pump | Non-compete agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Fair value	15		13
Life (years)	6 years		60 months
Trench safety, Power and HVAC, and Pump Solutions
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill			468	[1]	141	[1]	142	[1]	122	[1]
Trench safety, Power and HVAC, and Pump Solutions | National Pump
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	321
General rentals
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill			2,804	[1]	2,812	[1]	2,828	[1]	167	[1]
General rentals | National Pump
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 12

[1] The total carrying amount of goodwill for all periods in the table above is reflected net of $1,557 of accumulated impairment charges, which were primarily recorded in our general rentals segment.

[2] $321 of the goodwill was assigned to our trench safety, power and HVAC (heating, ventilating and air conditioning), and pump solutions segment and $12 of the goodwill was assigned to our general rentals segment. The level of goodwill that resulted from the merger is primarily reflective of National Pump's going-concern value, the value of National Pump's assembled workforce, new customer relationships expected to arise from the merger, and operational synergies that we expect to achieve that would not be available to other market participants. $348 of goodwill is expected to be deductible for income tax purposes.