Stock Based Compensation (Tables)

12 Months Ended

Dec. 31, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Accrual Adjustments

	2012		2011		2010
	Millions
Compensation Cost included in Operation and Maintenance Expense	$	25	$	23	$	29
Income Tax Benefit Recognized in Consolidated Statement of Operations	$	10	$	10	$	12

Stock Options Activity

Changes in stock options for 2012 are summarized as follows:

	Options	Weighted Average Exercise Price		Weighted Average Remaining Years Contractual Term	Aggregate Intrinsic Value
Outstanding as of January 1, 2012	3,272,300	$	32.78
Exercised	326,900	$	20.10
Outstanding as of December 31, 2012	2,945,400	$	34.19	5.3	$	1,509,670
Exercisable at December 31, 2012	2,750,325	$	34.24	5.2	$	1,506,268

Activity For Options Exercised

Activity for options exercised for the years ended December 31, 2012, 2011 and 2010 is shown below:

	2012		2011		2010
	Millions
Total Intrinsic Value of Options Exercised	$	4	$	2	$	1
Cash Received from Options Exercised	$	7	$	6	$	3
Tax Benefit Realized from Options Exercised	$	1	$	1	$	1

Restricted Stock Activity

Changes in restricted stock for the year ended December 31, 2012 are summarized as follows:

	Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Years Contractual Term	Aggregate Intrinsic Value
Non-vested as of January 1, 2012	70,300	$	32.83
Vested	1,500	$	44.44
Non-vested as of December 31, 2012	68,800	$	32.57	0.2	$	2,105,280

Restricted Stock Units Activity

Changes in restricted stock units for the year ended December 31, 2012 are summarized as follows:

	Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Years Contractual Term	Aggregate Intrinsic Value
Non-vested as of January 1, 2012	648,551	$	31.17
Granted	345,440	$	30.95
Vested	125,838	$	30.87
Canceled/Forfeited	33,626	$	31.24
Non-vested as of December 31, 2012	834,527	$	31.12	1.2	$	25,536,532

Performance Units Information

Changes in Performance Share Units for the year ended December 31, 2012 are summarized as follows:

	Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Years Contractual Term	Aggregate Intrinsic Value
Non-vested as of January 1, 2012	641,986	$	35.13
Granted	404,460	$	31.25
Vested	258,501	$	36.35
Canceled/Forfeited	37,952	$	33.51
Non-vested as of December 31, 2012	749,993	$	32.70	1.5	$	22,949,786