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Comprehensive income (loss) | 6 Months Ended
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Jun. 30, 2013
Comprehensive income (loss) [Abstract] |
Comprehensive income (loss) | Comprehensive income (loss) The after-tax changes in the components of accumulated other comprehensive loss as of June 30, 2013, were as follows:
| Net Unrealized Gain (Loss) on Derivative Instruments Qualifying as Hedges | Net Unrealized Gain (Loss) on Available-for-sale Investments | Postretirement Liability Adjustment | Foreign Currency Translation Adjustment | Total Accumulated Other Comprehensive Loss
| (In thousands)
Balance at December 31, 2012 | $ | 6,018 |  | $ | 119 |  | $ | (54,347 | ) | $ | (511 | ) | $ | (48,721 | )
Other comprehensive income (loss) before reclassifications | (5,594 | ) | (187 | ) | — |  | (302 | ) | (6,083 | )
Amounts reclassified from accumulated other comprehensive loss | (3,168 | ) | 79 |  | 1,072 |  | — |  | (2,017 | )
Net current-period other comprehensive income (loss) | (8,762 | ) | (108 | ) | 1,072 |  | (302 | ) | (8,100 | )
Balance at June 30, 2013 | $ | (2,744 | ) | $ | 11 |  | $ | (53,275 | ) | $ | (813 | ) | $ | (56,821 | )
Reclassifications out of accumulated other comprehensive loss were as follows:
| Three Months Ended | Six Months Ended | Location on Consolidated Statements of Income
| June 30, 2013 | June 30, 2013
| (In thousands) |
Reclassification adjustment for gain (loss) on derivative instruments included in net income |  |  |
Commodity derivative instruments | $ | 1,382 |  | $ | 5,896 |  | Operating revenues
Interest rate derivative instruments | (664 | ) | (780 | ) | Interest expense
| 718 |  | 5,116 |  |
| (322 | ) | (1,948 | ) | Income taxes
| 396 |  | 3,168 |  |
Amortization of postretirement liability losses included in net periodic benefit cost | (967 | ) | (1,934 | ) | (a)
| 543 |  | 862 |  | Income taxes
| (424 | ) | (1,072 | ) |
Reclassification adjustment for loss on available-for-sale investments included in net income | (67 | ) | (121 | ) | Other income
| 23 |  | 42 |  | Income taxes
| (44 | ) | (79 | ) |
Total reclassifications | $ | (72 | ) | $ | 2,017 |  |
(a) Included in net periodic benefit cost (credit). For more information, see Note 17.

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- Definition The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e637-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e681-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e689-108580 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=28358780&loc=SL7669619-108580 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e640-108580 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e716-108580 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e709-108580 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Reclassification Adjustments -URI http://asc.fasb.org/extlink&oid=6522872 + Details
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