Consolidated Statements of Capitalization (Parenthetical) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Common stock, par value	0.50	0.50
Long-Term Debt of Subsidiaries 0.00% To 0.99% [Member]
Interest rate range, minimum	0.00%	0.00%
Interest rate range, maximum	0.99%	0.99%
Maturity date range, start	2012	2012
Maturity date range, end	2034	2034
Long-Term Debt of Subsidiaries 1.00% To 1.99% [Member]
Interest rate range, minimum	1.00%	1.00%
Interest rate range, maximum	1.99%	1.99%
Maturity date range, start	2011	2011
Maturity date range, end	2035	2035
Long-Term Debt of Subsidiaries 2.00% To 2.99% [Member]
Interest rate range, minimum	2.00%	2.00%
Interest rate range, maximum	2.99%	2.99%
Maturity date range, start	2019	2019
Maturity date range, end	2029	2029
Long-Term Debt of Subsidiaries 3.00% To 3.99% [Member]
Interest rate range, minimum	3.00%	3.00%
Interest rate range, maximum	3.99%	3.99%
Maturity date range, start	2016	2016
Maturity date range, end	2030	2030
Long-Term Debt of Subsidiaries 4.00% To 4.99% [Member]
Interest rate range, minimum	4.00%	4.00%
Interest rate range, maximum	4.99%	4.99%
Maturity date range, start	2020	2020
Maturity date range, end	2043	2043
Long-Term Debt of Subsidiaries 5.00% To 5.99% [Member]
Interest rate range, minimum	5.00%	5.00%
Interest rate range, maximum	5.99%	5.99%
Maturity date range, start	2012	2012
Maturity date range, end	2043	2043
Long-Term Debt of Subsidiaries 6.00% To 6.99% [Member]
Interest rate range, minimum	6.00%	6.00%
Interest rate range, maximum	6.99%	6.99%
Maturity date range, start	2011	2011
Maturity date range, end	2036	2036
Long-Term Debt of Subsidiaries 7.00% To 7.99% [Member]
Interest rate range, minimum	7.00%	7.00%
Interest rate range, maximum	7.99%	7.99%
Maturity date range, start	2012	2012
Maturity date range, end	2025	2025
Long-Term Debt of Subsidiaries 8.00% To 8.99% [Member]
Interest rate range, minimum	8.00%	8.00%
Interest rate range, maximum	8.99%	8.99%
Maturity date range, start	2021	2021
Maturity date range, end	2025	2025
Long-Term Debt of Subsidiaries 9.00% To 9.99% [Member]
Interest rate range, minimum	9.00%	9.00%
Interest rate range, maximum	9.99%	9.99%
Maturity date range, start	2011	2011
Maturity date range, end	2026	2026
Long-Term Debt of Subsidiaries 10.40% [Member]
Interest rate range, minimum	10.40%	10.40%
Interest rate range, maximum	10.40%	10.40%
Maturity date range, start	2018	2018
Maturity date range, end	2018	2018
Notes Ranging From 4.62% To 4.87% [Member]
Interest rate range, minimum	4.62%	4.62%
Interest rate range, maximum	4.87%	4.87%
Maturity date range, start	2013	2013
Maturity date range, end	2024	2024
Notes Ranging From 5.01% To 5.95% [Member]
Interest rate range, minimum	5.01%	5.01%
Interest rate range, maximum	5.95%	5.95%
Maturity date range, start	2014	2014
Maturity date range, end	2037	2037