Stock-Based Compensation (tables)

12 Months Ended

Dec. 31, 2011

Share Based Compensation Abstract

Schedule Of Performance Based Award [Table Text Block]

Performance	Performance Share Awards Outstanding			2011		Cumulative Expense
Period	Threshold	Target	Maximum	Expense		At Dec. 31, 2011
2009-11	7,410	39,000	78,000	$	353	$	763
2010-12	n/a(1)	41,500	83,000		430		718
2011-13	n/a(1)	37,950	75,900		276	$	276
Total		118,450	236,900	$	1,059
(1)The threshold requirement was modified and is no longer applicable beginning in the 2010-12 performance period.

SOP Assumptions [Table Text Block]

		2011		2010		2009
Risk-free interest rate		2.0%		2.3%		2.0%
Expected life (in years)		4.5		4.7		4.7
Expected market price volatility factor		24.5%		23.2%		22.5%
Expected dividend yield		3.8%		3.8%		3.8%
Forfeiture rate		3.1%		3.2%		3.7%
Weighted average grant date fair value	$	6.73	$	6.36	$	5.46

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

			Weighted -		Intrinsic
	Option		Average		Value
	Shares		Price Per Share		(In millions)
Balance outstanding, Dec. 31, 2008	396,410	$	38.62	$	2.3
Granted	111,750		41.15		n/a
Exercised	(23,225)		30.92		0.3
Balance outstanding, Dec. 31, 2009	484,935		39.57		2.7
Granted	119,750		44.25		n/a
Exercised	(111,525)		39.01		0.9
Forfeited	(2,700)		43.00		n/a
Balance outstanding, Dec. 31, 2010	490,460		40.82		2.8
Granted	122,700		45.74		n/a
Exercised	(24,185)		33.88		0.3
Forfeited	(9,750)		44.38		n/a
Balance outstanding, Dec. 31, 2011	579,225	$	42.09	$	3.4
Exercisable, Dec. 31, 2011	311,951	$	40.20	$	2.4

Schedule Of Stock Based Compensation Capitalized Under LTIP SOP and ESPP [Table Text Block]

Thousands			2011		2010		2009
Operations and maintenance expense, for stock-based compensation		$	1,477	$	1,032	$	1,434
Income tax benefit			(597)		(418)		(559)
	Net stock-based compensation effect on net income	$	880	$	614	$	875
Amounts capitalized for stock-based compensation		$	261	$	182	$	229