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Employee Benefits (Tables) | 12 Months Ended
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Dec. 31, 2018
Retirement Benefits [Abstract] |
Reconciliation of the changes in the plans' benefit obligations and fair value of assets | The following tables provide a reconciliation of the changes in our plans' benefit obligations and fair value of assets:
|  | Pension Costs |  | OPEB Costs
(in millions) |  | 2018 |  | 2017 |  | 2018 |  | 2017
Change in benefit obligation |  |  |  |  |  |  |  |
Obligation at January 1 |  | $ | 3,163.7 |  |  | $ | 3,058.8 |  |  | $ | 818.5 |  |  | $ | 818.4 |
Service cost |  | 47.1 |  |  | 44.6 |  |  | 23.7 |  |  | 24.1 |
Interest cost |  | 114.3 |  |  | 121.8 |  |  | 29.9 |  |  | 32.9 |
Participant contributions |  | — |  |  | — |  |  | 15.5 |  |  | 13.4 |
Plan amendments |  | — |  |  | — |  |  | (3.5 | ) |  | (36.4 | )
Actuarial loss (gain) |  | (171.8 | ) |  | 162.6 |  |  | (222.6 | ) |  | 12.9 |
Benefit payments |  | (226.1 | ) |  | (224.1 | ) |  | (55.4 | ) |  | (48.8 | )
Federal subsidy on benefits paid |  | N/A |  |  | N/A |  |  | 1.0 |  |  | 2.0 |
Transfer |  | — |  |  | — |  |  | 1.1 |  |  | — |
Obligation at December 31 |  | $ | 2,927.2 |  |  | $ | 3,163.7 |  |  | $ | 608.2 |  |  | $ | 818.5 |
Change in fair value of plan assets |  |  |  |  |  |  |  |
Fair value at January 1 |  | $ | 2,966.8 |  |  | $ | 2,709.2 |  |  | $ | 841.5 |  |  | $ | 773.5 |
Actual return on plan assets |  | (122.2 | ) |  | 368.7 |  |  | (35.2 | ) |  | 95.9 |
Employer contributions |  | 72.3 |  |  | 113.0 |  |  | 5.3 |  |  | 7.5 |
Participant contributions |  | — |  |  | — |  |  | 15.5 |  |  | 13.4 |
Benefit payments |  | (226.1 | ) |  | (224.1 | ) |  | (55.4 | ) |  | (48.8 | )
Fair value at December 31 |  | $ | 2,690.8 |  |  | $ | 2,966.8 |  |  | $ | 771.7 |  |  | $ | 841.5 |
Funded status at December 31 |  | $ | (236.4 | ) |  | $ | (196.9 | ) |  | $ | 163.5 |  |  | $ | 23.0 |
Amounts recognized on the balance sheets at December 31 related to the funded status of the benefit plans | The amounts recognized on our balance sheets at December 31 related to the funded status of the benefit plans were as follows:
|  | Pension Costs |  | OPEB Costs
(in millions) |  | 2018 |  | 2017 |  | 2018 |  | 2017
Other long-term assets |  | $ | 139.1 |  |  | $ | 143.0 |  |  | $ | 210.8 |  |  | $ | 80.5 |
Pension and OPEB obligations |  | 375.5 |  |  | 339.9 |  |  | 47.3 |  |  | 57.5 |
Total net (liabilities) assets |  | $ | (236.4 | ) |  | $ | (196.9 | ) |  | $ | 163.5 |  |  | $ | 23.0 |
Information for pension plans with an accumulated benefit obligation in excess of plan assets | The following table shows information for pension plans with an accumulated benefit obligation in excess of plan assets. Amounts presented are as of December 31:
(in millions) |  | 2018 |  | 2017
Projected benefit obligation |  | $ | 1,930.8 |  |  | $ | 679.5 |
Accumulated benefit obligation |  | 1,882.2 |  |  | 630.3 |
Fair value of plan assets |  | 1,572.7 |  |  | 339.6 |
Amounts that had not yet been recognized in the entity's net periodic benefit cost | The following table shows the amounts that have not yet been recognized in our net periodic benefit cost as of December 31:
|  | Pension Costs |  | OPEB Costs
(in millions) |  | 2018 |  | 2017 |  | 2018 |  | 2017
Pre-tax accumulated other comprehensive loss (income) (1) |  |  |  |  |  |  |  |
Net actuarial loss (gain) |  | $ | 14.5 |  |  | $ | 10.0 |  |  | $ | (1.6 | ) |  | $ | (1.0 | )
Prior service credits |  | — |  |  | — |  |  | (0.1 | ) |  | (0.1 | )
Total |  | $ | 14.5 |  |  | $ | 10.0 |  |  | $ | (1.7 | ) |  | $ | (1.1 | )
Net regulatory assets (liabilities) (2) |  |  |  |  |  |  |  |
Net actuarial loss (gain) |  | $ | 1,184.1 |  |  | $ | 1,136.8 |  |  | $ | (133.0 | ) |  | $ | (4.7 | )
Prior service costs (credits) |  | 4.9 |  |  | 7.5 |  |  | (100.0 | ) |  | (111.8 | )
Total |  | $ | 1,189.0 |  |  | $ | 1,144.3 |  |  | $ | (233.0 | ) |  | $ | (116.5 | )
(1) | Amounts related to the nonregulated entities are included in accumulated other comprehensive loss (income).
(2) | Amounts related to the utilities and WBS are recorded as net regulatory assets or liabilities.
Estimated amounts that will be amortized into net periodic benefit cost | The following table shows the estimated amounts that will be amortized into net periodic benefit cost during 2019:
(in millions) |  | Pension Costs |  | OPEB Costs
Net actuarial loss (gain) |  | $ | 76.1 |  |  | $ | (5.7 | )
Prior service costs (credits) |  | 2.2 |  |  | (15.4 | )
Total 2019 – estimated amortization |  | $ | 78.3 |  |  | $ | (21.1 | )
Schedule of the components of net periodic benefit cost | The components of net periodic benefit cost (including amounts capitalized to our balance sheets) for the years ended December 31 were as follows:
|  | Pension Costs |  | OPEB Costs
(in millions) |  | 2018 |  | 2017 |  | 2016 |  | 2018 |  | 2017 |  | 2016
Service cost |  | $ | 47.1 |  |  | $ | 44.6 |  |  | $ | 45.4 |  |  | $ | 23.7 |  |  | $ | 24.1 |  |  | $ | 26.1 |
Interest cost |  | 114.3 |  |  | 121.8 |  |  | 130.8 |  |  | 29.9 |  |  | 32.9 |  |  | 37.0 |
Expected return on plan assets |  | (196.5 | ) |  | (195.7 | ) |  | (195.9 | ) |  | (59.5 | ) |  | (55.5 | ) |  | (52.7 | )
Plan settlement |  | 1.0 |  |  | 9.0 |  |  | 16.5 |  |  | — |  |  | — |  |  | — |
Amortization of prior service cost (credit) |  | 2.7 |  |  | 2.9 |  |  | 3.4 |  |  | (15.4 | ) |  | (12.3 | ) |  | (9.4 | )
Amortization of net actuarial loss |  | 94.0 |  |  | 86.1 |  |  | 82.9 |  |  | 1.0 |  |  | 3.1 |  |  | 8.5 |
Net periodic benefit cost (credit) |  | $ | 62.6 |  |  | $ | 68.7 |  |  | $ | 83.1 |  |  | $ | (20.3 | ) |  | $ | (7.7 | ) |  | $ | 9.5 |
Schedule of financial statement impacts from retrospective restatements | The impacts to our income statements from adoption of this standard are reflected in the table below.
|  | Year Ended December 31, 2017 |  | Year Ended December 31, 2016
(in millions) |  | Form 10-K Income Statement |  | Impact of ASU 2017-07 |  | Income Statement After Adoption |  | Form 10-K Income Statement |  | Impact of ASU 2017-07 |  | Income Statement After Adoption
Operating expenses |  |  |  |  |  |  |  |  |  |  |  |
Other operation and maintenance |  | $ | 2,047.0 |  |  | $ | 9.1 |  |  | $ | 2,056.1 |  |  | $ | 2,185.5 |  |  | $ | (14.2 | ) |  | $ | 2,171.3 |
Other expense |  |  |  |  |  |  |  |  |  |  |  |
Other income, net |  | 64.6 |  |  | 9.1 |  |  | 73.7 |  |  | 80.8 |  |  | (14.2 | ) |  | 66.6 |
Weighted-average assumptions used to determine benefit obligations and net periodic benefit cost for the plans | The weighted-average assumptions used to determine the benefit obligations for the plans were as follows for the years ended December 31:
|  | Pension |  | OPEB
|  | 2018 |  | 2017 |  | 2018 |  | 2017
Discount rate |  | 4.30% |  | 3.66% |  | 4.27% |  | 3.63%
Rate of compensation increase |  | 3.66% |  | 3.61% |  | N/A |  | N/A
Assumed medical cost trend rate (Pre 65) |  | N/A |  | N/A |  | 6.25% |  | 6.50%
Ultimate trend rate (Pre 65) |  | N/A |  | N/A |  | 5.00% |  | 5.00%
Year ultimate trend rate is reached (Pre 65) |  | N/A |  | N/A |  | 2024 |  | 2024
Assumed medical cost trend rate (Post 65) |  | N/A |  | N/A |  | 6.01% |  | 6.09%
Ultimate trend rate (Post 65) |  | N/A |  | N/A |  | 5.00% |  | 5.00%
Year ultimate trend rate is reached (Post 65) |  | N/A |  | N/A |  | 2028 |  | 2028
The weighted-average assumptions used to determine the net periodic benefit cost for the plans were as follows for the years ended December 31:
|  | Pension Costs
|  | 2018 |  | 2017 |  | 2016
Discount rate |  | 3.71% |  | 4.11% |  | 4.35%
Expected return on plan assets |  | 7.12% |  | 7.11% |  | 7.12%
Rate of compensation increase |  | 3.66% |  | 3.60% |  | 3.75%
|  | OPEB Costs
|  | 2018 |  | 2017 |  | 2016
Discount rate |  | 3.63% |  | 4.04% |  | 4.38%
Expected return on plan assets |  | 7.25% |  | 7.25% |  | 7.25%
Assumed medical cost trend rate (Pre 65) |  | 6.50% |  | 7.00% |  | 7.50%
Ultimate trend rate (Pre 65) |  | 5.00% |  | 5.00% |  | 5.00%
Year ultimate trend rate is reached (Pre 65) |  | 2024 |  | 2021 |  | 2021
Assumed medical cost trend rate (Post 65) |  | 6.09% |  | 7.00% |  | 7.50%
Ultimate trend rate (Post 65) |  | 5.00% |  | 5.00% |  | 5.00%
Year ultimate trend rate is reached (Post 65) |  | 2028 |  | 2021 |  | 2021
Effects of a one-percentage-point change in assumed health care cost trend rates | For the year ended December 31, 2018, a one-percentage-point change in assumed health care cost trend rates would have had the following effects:
(in millions) |  | 1% Increase |  | 1% Decrease
Effect on total of service and interest cost components of net periodic postretirement health care benefit cost |  | $ | 7.5 |  |  | $ | (5.9 | )
Effect on health care component of the accumulated postretirement benefit obligations |  | 44.3 |  |  | (37.1 | )
Investments recorded at fair value, by asset class | The following tables provide the fair values of our investments by asset class:
|  | December 31, 2018
|  | Pension Plan Assets |  | OPEB Assets
(in millions) |  | Level 1 |  | Level 2 |  | Level 3 |  | Total |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Asset Class |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity securities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
United States Equity |  | $ | 281.7 |  |  | $ | — |  |  | $ | — |  |  | $ | 281.7 |  |  | $ | 88.2 |  |  | $ | — |  |  | $ | — |  |  | $ | 88.2 |
International Equity |  | 279.7 |  |  | 0.7 |  |  | — |  |  | 280.4 |  |  | 92.2 |  |  | 0.2 |  |  | — |  |  | 92.4 |
Fixed income securities: * |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
United States Bonds |  | 123.7 |  |  | 838.8 |  |  | — |  |  | 962.5 |  |  | 119.6 |  |  | 150.8 |  |  | — |  |  | 270.4 |
International Bonds |  | 16.1 |  |  | 85.5 |  |  | — |  |  | 101.6 |  |  | 7.1 |  |  | 8.9 |  |  | — |  |  | 16.0 |
|  | $ | 701.2 |  |  | $ | 925.0 |  |  | $ | — |  |  | $ | 1,626.2 |  |  | $ | 307.1 |  |  | $ | 159.9 |  |  | $ | — |  |  | $ | 467.0 |
Investments measured at net asset value |  |  |  |  |  |  |  | $ | 1,064.6 |  |  |  |  |  |  |  |  | $ | 304.7 |
Total |  | $ | 701.2 |  |  | $ | 925.0 |  |  | $ | — |  |  | $ | 2,690.8 |  |  | $ | 307.1 |  |  | $ | 159.9 |  |  | $ | — |  |  | $ | 771.7 |
* | This category represents investment grade bonds of United States and foreign issuers denominated in United States dollars from diverse industries.
|  | December 31, 2017
|  | Pension Plan Assets |  | OPEB Assets
(in millions) |  | Level 1 |  | Level 2 |  | Level 3 |  | Total |  | Level 1 |  | Level 2 |  | Level 3 |  | Total
Asset Class |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash and cash equivalents |  | $ | — |  |  | $ | 53.6 |  |  | $ | — |  |  | $ | 53.6 |  |  | $ | 19.6 |  |  | $ | 2.3 |  |  | $ | — |  |  | $ | 21.9 |
Equity securities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
United States Equity |  | 345.0 |  |  | 0.1 |  |  | — |  |  | 345.1 |  |  | 101.0 |  |  | — |  |  | — |  |  | 101.0 |
International Equity |  | 352.1 |  |  | — |  |  | 0.8 |  |  | 352.9 |  |  | 115.3 |  |  | — |  |  | 0.2 |  |  | 115.5 |
Fixed income securities: * |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
United States Bonds |  | 138.6 |  |  | 892.9 |  |  | — |  |  | 1,031.5 |  |  | 121.0 |  |  | 148.1 |  |  | — |  |  | 269.1 |
International Bonds |  | 17.8 |  |  | 86.8 |  |  | — |  |  | 104.6 |  |  | 7.2 |  |  | 9.1 |  |  | — |  |  | 16.3 |
Private Equity and Real Estate |  | — |  |  | 154.1 |  |  | 100.1 |  |  | 254.2 |  |  | — |  |  | 6.6 |  |  | 7.7 |  |  | 14.3 |
|  | $ | 853.5 |  |  | $ | 1,187.5 |  |  | $ | 100.9 |  |  | $ | 2,141.9 |  |  | $ | 364.1 |  |  | $ | 166.1 |  |  | $ | 7.9 |  |  | $ | 538.1 |
Investments measured at net asset value |  |  |  |  |  |  |  | $ | 824.9 |  |  |  |  |  |  |  |  | $ | 303.4 |
Total |  | $ | 853.5 |  |  | $ | 1,187.5 |  |  | $ | 100.9 |  |  | $ | 2,966.8 |  |  | $ | 364.1 |  |  | $ | 166.1 |  |  | $ | 7.9 |  |  | $ | 841.5 |
* | This category represents investment grade bonds of United States and foreign issuers denominated in United States dollars from diverse industries.
Reconciliation of changes in the fair value of plan assets categorized as Level 3 measurements | The following tables set forth a reconciliation of changes in the fair value of pension and OPEB plan assets categorized as Level 3 in the fair value hierarchy:
|  | Private Equity and Real Estate |  | International Equity
(in millions) |  | Pension |  | OPEB |  | Pension |  | OPEB
Beginning balance at January 1, 2018 |  | $ | 100.1 |  |  | $ | 7.7 |  |  | $ | 0.8 |  |  | $ | 0.2 |
Realized and unrealized gains (losses) |  | 8.0 |  |  | 1.1 |  |  | (0.1 | ) |  | — |
Purchases |  | 18.3 |  |  | 1.5 |  |  | — |  |  | — |
Liquidations |  | (1.7 | ) |  | (0.2 | ) |  | — |  |  | — |
Transfers out of level 3 |  | (124.7 | ) |  | (10.1 | ) |  | (0.7 | ) |  | (0.2 | )
Ending balance at December 31, 2018 |  | $ | — |  |  | $ | — |  |  | $ | — |  |  | $ | — |
|  | Private Equity and Real Estate |  | International Equity |  | U.S. Bonds
(in millions) |  | Pension |  | OPEB |  | Pension |  | OPEB |  | Pension
Beginning balance at January 1, 2017 |  | $ | 14.6 |  |  | $ | 1.3 |  |  | $ | — |  |  | $ | — |  |  | $ | 0.8 |
Realized and unrealized gains (losses) |  | 2.8 |  |  | 0.3 |  |  | (0.2 | ) |  | — |  |  | (0.8 | )
Purchases |  | 55.5 |  |  | 3.6 |  |  | 1.0 |  |  | 0.2 |  |  | — |
Transfers into level 3 |  | 27.2 |  |  | 2.5 |  |  | — |  |  | — |  |  | — |
Ending balance at December 31, 2017 |  | $ | 100.1 |  |  | $ | 7.7 |  |  | $ | 0.8 |  |  | $ | 0.2 |  |  | $ | — |
Schedule of expected future benefit payments | The following table shows the payments, reflecting expected future service, that we expect to make for pension and OPEB:
(in millions) |  | Pension Costs |  | OPEB Costs
2019 |  | $ | 239.0 |  |  | $ | 35.4 |
2020 |  | 233.0 |  |  | 39.6 |
2021 |  | 230.9 |  |  | 41.3 |
2022 |  | 225.7 |  |  | 41.6 |
2023 |  | 215.8 |  |  | 42.5 |
2024-2028 |  | 985.5 |  |  | 213.6 |

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- Definition Tabular disclosure of the amounts that are recognized in the balance sheet (or statement of financial position) for pension plans and/or other employee benefit plans, showing separately the assets and current and noncurrent liabilities (if applicable) recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 + Details
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- Definition Tabular disclosure of the amounts related to pension plans and/or other employee benefit plans in accumulated other comprehensive income or loss that have not yet been recognized as components of net periodic benefit cost, such as the net gain (loss), net prior service cost or credit, and net transition asset or obligation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920 + Details
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- Definition Schedule of financial statement impacts from retrospective restatements due to adoption of a new accounting standard. [Table Text Block] + References No definition available. + Details
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