Share Plans (Tables)

12 Months Ended

Dec. 31, 2014

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

	December 31
In millions	2014		2013		2012
Restricted stock units	$	22.6	$	20.2	$	24.2
Stock options	11.0		10.9		11.6
Total share-based compensation expense	$	33.6	$	31.1	$	35.8

Stock Option Activity

The following table summarizes stock option activity under all plans for the year ended December 31, 2014:

Shares and intrinsic value in millions	Number of shares		Weighted- average exercise price		Weighted- average remaining contractual life (years)	Aggregate intrinsic value
Outstanding as of January 1, 2014	6.2		$	35.53
Granted	0.5		77.93
Exercised	(0.9	)	35.53
Forfeited	(0.1	)	49.29
Outstanding as of December 31, 2014	5.7		$	39.08	5.1	$	157.8
Options exercisable as of December 31, 2014	4.5		$	33.53	4.2	$	144.0
Options expected to vest as of December 31, 2014	1.2		$	59.46	8.2	$	13.8

Stock Option Fair Value Assumptions

We estimated the fair value of each stock option award on the date of grant using a Black-Scholes option pricing model, modified for dividends and using the following weighted average assumptions:

	December 31
	2014		2013		2012
	Granted by Pentair plans		Granted by Pentair plans		Assumed in Merger		Granted by Pentair plans
Risk-free interest rate	1.44	%	0.69	%	0.02 - 0.68%		0.96	%
Expected dividend yield	1.46	%	2.01	%	2.12	%	2.48	%
Expected share price volatility	35.3	%	36.0	%	33.0	%	36.5	%
Expected term (years)	5.6		5.7		0.1 - 5.1		5.7

Restricted Stock Activity

The following table summarizes restricted stock unit activity under all plans for the year ended December 31, 2014:

Shares in millions	Number of shares		Weighted average grant date fair value
Outstanding as of January 1, 2014	1.3		$	43.25
Granted	0.3		78.39
Vested	(0.4	)	39.68
Forfeited	(0.1	)	46.42
Outstanding as of December 31, 2014	1.1		$	50.55