Common Equity (Tables)

12 Months Ended

Dec. 31, 2014

Stockholders' Equity Note [Abstract]

Recorded pre-tax share-based compensation expense and related tax benefit for share-based awards made to employees and directors

The following table summarizes recorded pre-tax share-based compensation expense and the related tax benefit for share-based awards made to our employees and directors as of December 31:

	2014		2013		2012
	(Millions of Dollars)
Performance units	$	15.4	$	12.7	$	16.3
Stock options	3.7		3.9		2.7
Restricted stock	2.8		2.4		3.0
Share-based compensation expense	$	21.9	$	19.0	$	22.0
Related Tax Benefit	$	8.8	$	7.6	$	8.8

Stock option activity

The following is a summary of our stock option activity during 2014:

Stock Options	Number of Options		Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value (Millions)
Outstanding as of January 1, 2014	8,089,710		$	26.84
Granted	899,500		$	41.03
Exercised	(2,201,821	)	$	22.85
Forfeited	(17,195	)	$	37.42
Outstanding as of December 31, 2014	6,770,194		$	29.99	5.7	$	154.0
Exercisable as of December 31, 2014	3,890,339		$	24.10	3.9	$	111.4

Stock options outstanding

The following table summarizes information about stock options outstanding as of December 31, 2014:

	Options Outstanding				Options Exercisable
		Weighted-Average				Weighted-Average
Range of Exercise Prices	Number of Options	Exercise Price		Remaining Contractual Life (Years)	Number of Options	Exercise Price		Remaining Contractual Life (Years)
$17.10  to  $21.11	1,498,071	$	20.86	3.5	1,498,071	$	20.86	3.5
$23.88  to  $29.35	2,153,513	$	25.06	3.7	2,153,513	$	25.06	3.7
$34.88  to  $41.03	3,118,610	$	37.79	8.0	238,755	$	35.88	7.4
	6,770,194	$	29.99	5.7	3,890,339	$	24.10	3.9

Non-vested options

The following table summarizes information about our non-vested options during 2014:

Non-Vested Stock Options	Number of Options		Weighted- Average Fair Value
Non-Vested as of January 1, 2014	2,380,790		$	3.38
Granted	899,500		$	4.18
Vested	(383,240	)	$	3.26
Forfeited	(17,195	)	$	3.56
Non-Vested as of December 31, 2014	2,879,855		$	3.65

Restricted stock activity

Restricted Shares:   The Compensation Committee has also approved restricted stock grants to certain key employees and directors. The following restricted stock activity occurred during 2014:

Restricted Shares	Number of Shares		Weighted-Average Market Price
Outstanding as of January 1, 2014	150,698
Granted	71,504		$	40.96
Released	(63,509	)	$	33.02
Forfeited	(3,214	)	$	38.47
Outstanding as of December 31, 2014	155,479