Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 34,599	$ 46,107	$ 83,903		$ 60,479
Receivables, net	727,030	630,243
Inventories	226,583	238,273
Prepayments and other current assets	81,304	48,461
Current assets held for sale	479	14,391
Total current assets	1,069,995	977,475
Investments	137,613	125,866
Property, plant and equipment (Note 1)	6,770,829	6,510,229
Less accumulated depreciation, depletion and amortization	2,691,641	2,578,902	2,489,322
Net property, plant and equipment	4,079,188	3,931,327	3,898,380
Deferred charges and other assets:
Goodwill (Note 3)	631,791	631,791	635,204	[1]
Other intangible assets, net (Note 3)	3,837	5,925
Other	407,850	415,419
Noncurrent assets held for sale	4,392	196,664
Total deferred charges and other assets	1,047,870	1,249,799
Total assets	6,334,666	6,284,467	$ 6,565,154
Current liabilities:
Long-term debt due within one year	148,499	43,598
Accounts payable	312,327	279,962
Taxes payable	42,537	48,164
Dividends payable	38,573	37,767
Accrued compensation	72,919	65,867
Other accrued liabilities	186,010	184,377
Current liabilities held for sale	11,993	9,924
Total current liabilities	812,858	669,659
Long-term debt (Note 6)	1,566,354	1,746,561
Deferred credits and other liabilities:
Deferred income taxes	347,271	668,226
Other	1,179,140	883,777
Total deferred credits and other liabilities	1,526,411	1,552,003
Commitments and contingencies (Notes 14, 16 and 17)
Stockholders' equity:
Preferred stocks (Note 8)	0	15,000
Common stockholders' equity:
Common stock (Note 9) Authorized - 500,000,000 shares, $1.00 par value Issued - 195,843,297 shares in 2017 and 2016	195,843	195,843
Other paid-in capital	1,233,412	1,232,478
Retained earnings	1,040,748	912,282
Accumulated other comprehensive loss	(37,334)	(35,733)
Treasury stock at cost - 538,921 shares	(3,626)	(3,626)
Total common stockholders' equity	2,429,043	2,301,244
Total stockholders' equity	2,429,043	2,316,244
Total liabilities and stockholders' equity	$ 6,334,666	$ 6,284,467

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