| Accumulated other comprehensive income (loss) |
The following table sets forth the balance in accumulated other comprehensive income (loss) for the period indicated: | | | | | | | | | | | | | | | | | | Unrealized Gains (Losses) on Risk- Management Assets/Liabilities (a) | | Unrealized Holding Gains (Losses) on Investment Securities (a) | | Pension and Postretirement Benefit Plan Obligations (a) (b) | | Accumulated Other Comprehensive Income (Loss) (a) | | (Thousands of dollars) | January 1, 2015 | $ | (37,349 | ) | | $ | 955 |
| | $ | (99,959 | ) | | $ | (136,353 | ) | Other comprehensive income (loss) before reclassifications | 3,661 |
| | (955 | ) | | 65 |
| | 2,771 |
| Amounts reclassified from accumulated other comprehensive income (loss) | (9,785 | ) | | — |
| | 7,255 |
| | (2,530 | ) | Net current period other comprehensive income (loss) attributable to ONEOK | (6,124 | ) | | (955 | ) | | 7,320 |
| | 241 |
| September 30, 2015 | $ | (43,473 | ) | | $ | — |
| | $ | (92,639 | ) | | $ | (136,112 | ) |
(a) All amounts are presented net of tax. (b) Includes amounts related to supplemental executive retirement plan.
|
| Disclosure of Reclassification Amount [Text Block] |
The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) in our Consolidated Statements of Income for the periods indicated: | | | | | | | | | | | | | | | | | | | | Details about Accumulated Other Comprehensive Income (Loss) Components | | Three Months Ended | | Nine Months Ended | | Affected Line Item in the Consolidated Statements of Income | | September 30, | | September 30, | | | 2015 | | 2014 | | 2015 | | 2014 | | | | (Thousands of dollars) | | | Unrealized (gains) losses on risk-management assets/liabilities | | | | | | | | | | | Commodity contracts | | $ | (22,770 | ) | | $ | 355 |
| | $ | (54,020 | ) | | $ | 31,961 |
| | Commodity sales revenues | Interest-rate contracts | | 4,554 |
| | 3,525 |
| | 12,869 |
| | 18,372 |
| | Interest expense | | | (18,216 | ) | | 3,880 |
| | (41,151 | ) | | 50,333 |
| | Income before income taxes | | | 2,957 |
| | (748 | ) | | 5,621 |
| | (9,845 | ) | | Income tax expense | | | (15,259 | ) | | 3,132 |
| | (35,530 | ) | | 40,488 |
| | Income from continuing operations | | | — |
| | — |
| | — |
| | 7,682 |
| | Income (loss) from discontinued operations | | | (15,259 | ) |
| 3,132 |
| | (35,530 | ) | | 48,170 |
| | Net income | Noncontrolling interests | | (10,150 | ) | | 1,928 |
| | (25,745 | ) | | 24,574 |
| | Less: Net income attributable to noncontrolling interests | | | $ | (5,109 | ) | | $ | 1,204 |
| | $ | (9,785 | ) | | $ | 23,596 |
| | Net income attributable to ONEOK | | | | | | | | | | | | | | | | | | | | | | | Pension and postretirement benefit plan obligations (a) | | | | | | | | | | | Amortization of net loss | | $ | 4,422 |
| | $ | 4,009 |
| | $ | 13,268 |
| | $ | 11,936 |
| | | Amortization of unrecognized prior service cost | | (392 | ) | | (368 | ) | | (1,176 | ) | | (1,102 | ) | | | | | 4,030 |
| | 3,641 |
| | 12,092 |
| | 10,834 |
| | Income before income taxes | | | (1,612 | ) | | (1,456 | ) | | (4,837 | ) | | (4,334 | ) | | Income tax expense | | | 2,418 |
| | 2,185 |
| | 7,255 |
| | 6,500 |
| | Income from continuing operations | | | — |
| | — |
| | — |
| | 1,648 |
| | Income from discontinued operations | | | $ | 2,418 |
| | $ | 2,185 |
| | $ | 7,255 |
| | $ | 8,148 |
| | Net income attributable to ONEOK | | | | | | | | | | | | Total reclassifications for the period attributable to ONEOK | | $ | (2,691 | ) | | $ | 3,389 |
| | $ | (2,530 | ) | | $ | 31,744 |
| | Net income attributable to ONEOK |
(a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost. See Note K for additional detail of our net periodic benefit cost. |