Acquisitions (Pro Forma) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Apr. 30, 2014
Business Acquisition [Line Items]
Revenues	$ 1,523,000,000	$ 1,550,000,000	$ 1,429,000,000	$ 1,315,000,000	$ 1,564,000,000	$ 1,544,000,000	$ 1,399,000,000	$ 1,178,000,000	$ 5,817,000,000	$ 5,685,000,000	$ 4,955,000,000
Pro forma revenues										5,747,000,000	5,163,000,000
Historic pretax income									963,000,000	850,000,000	605,000,000
Pro forma pretax income (loss), before adjustments										870,000,000	667,000,000
Pro forma pretax income (loss)										923,000,000	518,000,000
Gains (losses) on extinguishment of debt									$ (123,000,000)	(80,000,000)	(1,000,000)
National Pump
Business Acquisition [Line Items]
Revenues										62,000,000	208,000,000
Historic pretax income										20,000,000	62,000,000
Impact of fair value mark-ups/useful life changes on depreciation
Business Acquisition [Line Items]
Pro forma adjustments to pretax income										(1,000,000)	(4,000,000)
Intangible asset amortization
Business Acquisition [Line Items]
Pro forma adjustments to pretax income										(12,000,000)	(52,000,000)
Interest expense
Business Acquisition [Line Items]
Pro forma adjustments to pretax income										58,000,000	(95,000,000)
Elimination of historic National Pump interest
Business Acquisition [Line Items]
Pro forma adjustments to pretax income										0	2,000,000
Elimination of merger costs
Business Acquisition [Line Items]
Pro forma adjustments to pretax income										$ 8,000,000	$ 0
Add-on to Senior Notes 6 1/8 percent | Senior notes
Business Acquisition [Line Items]
Debt instrument, face amount								525,000,000				$ 525,000,000
Add-on to Senior Notes 6 1/8 percent | Senior notes | National Pump
Business Acquisition [Line Items]
Stated interest rate												6.125%
5 3/4 percent Senior Notes
Business Acquisition [Line Items]
Stated interest rate	5.75%				5.75%				5.75%	5.75%
5 3/4 percent Senior Notes | Senior notes
Business Acquisition [Line Items]
Debt instrument, face amount								$ 850,000,000				$ 850,000,000
5 3/4 percent Senior Notes | Senior notes | National Pump
Business Acquisition [Line Items]
Stated interest rate												5.75%
Senior Notes 9.25 Percent
Business Acquisition [Line Items]
Gains (losses) on extinguishment of debt										$ (64,000,000)
Senior Notes 9.25 Percent | Senior notes | National Pump
Business Acquisition [Line Items]
Stated interest rate												9.25%