Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012
Current assets:
Cash and cash equivalents	$ 74,149		$ 49,042		$ 91,389
Receivables, net	635,564		678,123		539,589
Inventories	334,872		317,415		313,341
Deferred income taxes	29,885		22,846		42,239
Commodity derivative instruments	5,936		18,304		26,698
Prepayments and other current assets	68,828		42,351		64,897
Total current assets	1,149,234		1,128,081		1,078,153
Investments	106,846		103,243		113,799
Property, plant and equipment	8,303,065		8,107,751		7,798,770
Less accumulated depreciation, depletion and amortization	3,678,535		3,608,912		3,419,574
Net property, plant and equipment	4,624,530		4,498,839		4,379,196
Deferred charges and other assets:
Goodwill	636,039	[1]	636,039	[1]	635,389	[1]
Other intangible assets, net	16,318		17,129		19,991
Other	295,215		299,160		312,103
Total deferred charges and other assets	947,572		952,328		967,483
Total assets	6,828,182		6,682,491		6,538,631
Current liabilities:
Short-term borrowings	37,500		28,200		0
Long-term debt due within one year	171,094		134,108		202,215
Accounts payable	375,942		388,015		321,369
Taxes payable	55,748		46,475		51,019
Dividends payable	32,744		171		31,800
Accrued compensation	31,382		48,448		28,463
Commodity derivative instruments	7,379		0		20,183
Other accrued liabilities	205,394		204,698		255,172
Total current liabilities	917,183		850,115		910,221
Long-term debt	1,618,569		1,610,867		1,213,974
Deferred credits and other liabilities:
Deferred income taxes	802,805		755,102		798,669
Other liabilities	814,643		818,159		842,169
Total deferred credits and other liabilities	1,617,448		1,573,261		1,640,838
Equity:
Preferred stocks	15,000		15,000		15,000
Common stockholders' equity:
Shares issued - 189,369,450 at March 31, 2013 and 2012 and December 31, 2012	189,369		189,369		189,369
Other paid-in capital	1,038,970		1,039,080		1,035,800
Retained earnings	1,480,784		1,457,146		1,589,985
Accumulated other comprehensive loss	(56,615)		(48,721)		(52,930)
Treasury stock at cost - 538,921 shares	(3,626)		(3,626)		(3,626)
Total common stockholders' equity	2,648,882		2,633,248		2,758,598
Total stockholders' equity	2,663,882		2,648,248		2,773,598
Noncontrolling interest	11,100		0		0
Total equity	2,674,982		2,648,248		2,773,598
Total liabilities and equity	$ 6,828,182		$ 6,682,491		$ 6,538,631

[1] Balance is presented net of accumulated impairment of $12.3 million at the pipeline and energy services segment, which occurred in prior periods.