Acquisitions and Divestitures Acquisitions (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016
Business Acquisition [Line Items]
Revenue, Net	$ 3,216	$ 3,337
Purchase price of business, net of cash acquired	$ 16	$ 6
Pentair's Valves & Controls [Member]
Business Acquisition [Line Items]
Revenue, Net			$ 1,600
Purchase price of business, net of cash acquired			$ 3,150