Retirement, Other Postretirement Benefits, and Defined Contribution Plans (Details 4) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Qualified Pension [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	$ 3,399,916	$ 3,216,268	$ 2,607,274
Qualified Pension [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		103,731
Qualified Pension [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	380,558
Qualified Pension [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		298,760
Qualified Pension [Member] | Equity securities [Member] | Preferred [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		8,354
Qualified Pension [Member] | Subsidiaries' Preferred Stock | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	11,752
Qualified Pension [Member] | Common Stock [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	1,010,491	1,375,531
Qualified Pension [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	1,074,178	657,075
Qualified Pension [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	300,246	263,081
Qualified Pension [Member] | Registered Investment Companies [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	497,598	385,020
Qualified Pension [Member] | Fixed Income Securities Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		108,305
Qualified Pension [Member] | Other [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	101,674
Qualified Pension [Member] | Insurance Company General Account [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	34,696	33,439
Qualified Pension [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	3,411,193	3,233,296
Qualified Pension [Member] | Cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	75	321
Qualified Pension [Member] | Other Pending Transactions [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	(9,238)	(14,954)
Qualified Pension [Member] | Other Postretirement Assets Included In Total Investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	(2,114)	(2,395)
Qualified Pension [Member] | Level 1 [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 1 [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		103,731
Qualified Pension [Member] | Level 1 [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Qualified Pension [Member] | Level 1 [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 1 [Member] | Equity securities [Member] | Preferred [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 1 [Member] | Subsidiaries' Preferred Stock | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	3,738
Qualified Pension [Member] | Level 1 [Member] | Common Stock [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	1,010,491	1,375,531
Qualified Pension [Member] | Level 1 [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 1 [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	142,509	75,124
Qualified Pension [Member] | Level 1 [Member] | Registered Investment Companies [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	53,323	0
Qualified Pension [Member] | Level 1 [Member] | Fixed Income Securities Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 1 [Member] | Other [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Qualified Pension [Member] | Level 1 [Member] | Insurance Company General Account [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 1 [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	1,210,061	1,554,386
Qualified Pension [Member] | Level 1 [Member] | Cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 1 [Member] | Other Pending Transactions [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 1 [Member] | Other Postretirement Assets Included In Total Investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 2 [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 2 [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 2 [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	380,558
Qualified Pension [Member] | Level 2 [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		298,760
Qualified Pension [Member] | Level 2 [Member] | Equity securities [Member] | Preferred [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		8,354
Qualified Pension [Member] | Level 2 [Member] | Subsidiaries' Preferred Stock | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	8,014
Qualified Pension [Member] | Level 2 [Member] | Common Stock [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 2 [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	1,074,178	657,075
Qualified Pension [Member] | Level 2 [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	157,737	187,957
Qualified Pension [Member] | Level 2 [Member] | Registered Investment Companies [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	444,275	385,020
Qualified Pension [Member] | Level 2 [Member] | Fixed Income Securities Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		108,305
Qualified Pension [Member] | Level 2 [Member] | Other [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	101,674
Qualified Pension [Member] | Level 2 [Member] | Insurance Company General Account [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	34,696	33,439
Qualified Pension [Member] | Level 2 [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	2,201,132	1,678,910
Qualified Pension [Member] | Level 2 [Member] | Cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 2 [Member] | Other Pending Transactions [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 2 [Member] | Other Postretirement Assets Included In Total Investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 3 [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Qualified Pension [Member] | Level 3 [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 3 [Member] | Equity securities [Member] | Preferred [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 3 [Member] | Subsidiaries' Preferred Stock | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Qualified Pension [Member] | Level 3 [Member] | Common Stock [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Registered Investment Companies [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Fixed Income Securities Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Qualified Pension [Member] | Level 3 [Member] | Other [Member] | Corporate debt instruments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Qualified Pension [Member] | Level 3 [Member] | Insurance Company General Account [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Other Pending Transactions [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Qualified Pension [Member] | Level 3 [Member] | Other Postretirement Assets Included In Total Investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Other Postretirement Trusts [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	427,172	404,430	362,399
Other Postretirement Trusts [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		4,014
Other Postretirement Trusts [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	42,807	37,128
Other Postretirement Trusts [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	208,812	211,835
Other Postretirement Trusts [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	99,728	90,149
Other Postretirement Trusts [Member] | Registered Investment Companies [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	4,659
Other Postretirement Trusts [Member] | Other [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		58,716
Other Postretirement Trusts [Member] | Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	69,287
Other Postretirement Trusts [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	425,293	401,842
Other Postretirement Trusts [Member] | Other Pending Transactions [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	(235)	193
Other Postretirement Trusts [Member] | Other Postretirement Assets Included In Total Investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	2,114	2,395
Other Postretirement Trusts [Member] | Level 1 [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		4,014
Other Postretirement Trusts [Member] | Level 1 [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Other Postretirement Trusts [Member] | Level 1 [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Other Postretirement Trusts [Member] | Level 1 [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	42,577	37,823
Other Postretirement Trusts [Member] | Level 1 [Member] | Registered Investment Companies [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	4,659
Other Postretirement Trusts [Member] | Level 1 [Member] | Other [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Other Postretirement Trusts [Member] | Level 1 [Member] | Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Other Postretirement Trusts [Member] | Level 1 [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	47,236	41,837
Other Postretirement Trusts [Member] | Level 2 [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Other Postretirement Trusts [Member] | Level 2 [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	42,807	37,128
Other Postretirement Trusts [Member] | Level 2 [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	208,812	211,835
Other Postretirement Trusts [Member] | Level 2 [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	57,151	52,326
Other Postretirement Trusts [Member] | Level 2 [Member] | Registered Investment Companies [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Other Postretirement Trusts [Member] | Level 2 [Member] | Other [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		58,716
Other Postretirement Trusts [Member] | Level 2 [Member] | Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	69,287
Other Postretirement Trusts [Member] | Level 2 [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	378,057	360,005
Other Postretirement Trusts [Member] | Level 3 [Member] | Fixed Income Securities [Member] | Interest-bearing cash [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Other Postretirement Trusts [Member] | Level 3 [Member] | Corporate debt instruments [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Other Postretirement Trusts [Member] | Level 3 [Member] | Common Collective Trusts [Member] | Equity securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Other Postretirement Trusts [Member] | Level 3 [Member] | U.S. Government securities [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0	0
Other Postretirement Trusts [Member] | Level 3 [Member] | Registered Investment Companies [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Other Postretirement Trusts [Member] | Level 3 [Member] | Other [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets		0
Other Postretirement Trusts [Member] | Level 3 [Member] | Other [Member] | Fixed Income Securities [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	0
Other Postretirement Trusts [Member] | Level 3 [Member] | Total investments [Member]
Investments held for qualified pension and other postretirement plans measured at fair value
Fair Value of Plan Assets	$ 0	$ 0