Consolidated Statements Of Capitalization (Parenthetical) (USD $)	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 0.00% To 0.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 0.00% To 0.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 1.00% To 1.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 1.00% To 1.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 2.00% To 2.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 2.00% To 2.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 3.00% To 3.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 3.00% To 3.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 4.00% To 4.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 4.00% To 4.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 5.00% To 5.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 5.00% To 5.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 6.00% To 6.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 6.00% To 6.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 7.00% To 7.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 7.00% To 7.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 8.00% To 8.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 8.00% To 8.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 9.00% To 9.99% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 9.00% To 9.99% [Member]	Jun. 30, 2012 Long-Term Debt Of Subsidiaries 10.40% [Member]	Dec. 31, 2011 Long-Term Debt Of Subsidiaries 10.40% [Member]	Jun. 30, 2012 Notes at 3.57% due 2027 [Member]	Dec. 31, 2011 Notes at 3.57% due 2027 [Member]	Jun. 30, 2012 Notes Ranging From 4.62% To 4.87% [Member]	Dec. 31, 2011 Notes Ranging From 4.62% To 4.87% [Member]	Jun. 30, 2012 Notes Ranging From 5.01% To 5.95% [Member]	Dec. 31, 2011 Notes Ranging From 5.01% To 5.95% [Member]
Interest rate																							3.57%	3.57%
Interest rate range, minimum	0.00%	0.00%	1.00%	1.00%	2.00%	2.00%	3.00%	3.00%	4.00%	4.00%	5.00%	5.00%	6.00%	6.00%	7.00%	7.00%	8.00%	8.00%	9.00%	9.00%	10.40%	10.40%			4.62%	4.62%	5.01%	5.01%
Interest rate range, maximum	0.99%	0.99%	1.99%	1.99%	2.99%	2.99%	3.99%	3.99%	4.99%	4.99%	5.99%	5.99%	6.99%	6.99%	7.99%	7.99%	8.99%	8.99%	9.99%	9.99%	10.40%	10.40%			4.87%	4.87%	5.95%	5.95%
Maturity date range, start	2024	2024	2014	2014	2024	2024	2016	2016	2020	2020	2012	2012	2015	2015	2012	2012	2021	2021	2013	2013	2018	2018			2013	2013	2014	2014
Maturity date range, end	2034	2034	2035	2035	2031	2031	2030	2030	2043	2043	2043	2043	2036	2036	2027	2027	2025	2025	2026	2026	2018	2018			2024	2024	2037	2037
Maturity date																							2027	2027