Available-for-sale Securities, Gross Unrealized Gain

$ 295,700,000

$ 240,300,000

Available-for-sale Securities, Gross Unrealized Loss

39,300,000

58,500,000

Investments [Abstract]

Equity investments in unconsolidated subsidiaries

85,500,000

87,100,000

Miscellaneous investments

43,400,000

41,900,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

26,344,000

33,281,000

1,453,361,000

1,445,197,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Commingled funds

469,692,000

457,986,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | International equity funds

78,812,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Private equity investments

63,096,000

52,143,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Real estate

49,421,000

45,564,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Government securities

34,393,000

34,304,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | U.S. corporate bonds

80,647,000

80,275,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | International corporate bonds

15,919,000

15,025,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Municipal bonds

225,508,000

241,112,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Asset-backed securities

9,218,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Mortgage-backed securities

24,097,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Cost | Common stock

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

376,214,000

406,695,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value

26,344,000

33,281,000

1,709,717,000

^[1]

1,627,026,000

^[2]

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Commingled funds

483,482,000

452,227,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | International equity funds

87,748,000

81,671,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Private equity investments

81,123,000

62,696,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Real estate

65,658,000

57,368,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Government securities

30,545,000

27,628,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | U.S. corporate bonds

84,230,000

83,538,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | International corporate bonds

16,432,000

15,358,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Municipal bonds

228,506,000

232,016,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Asset-backed securities

9,334,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Mortgage-backed securities

24,250,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Common stock

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

572,065,000

581,243,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1

26,344,000

33,281,000

598,409,000

614,524,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Commingled funds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | International equity funds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Private equity investments

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Real estate

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Government securities

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | U.S. corporate bonds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | International corporate bonds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Municipal bonds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Asset-backed securities

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Mortgage-backed securities

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 1 | Common stock

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

572,065,000

581,243,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2

964,527,000

892,438,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Commingled funds

483,482,000

452,227,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | International equity funds

87,748,000

81,671,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Private equity investments

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Real estate

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Government securities

30,545,000

27,628,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | U.S. corporate bonds

84,230,000

83,538,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | International corporate bonds

16,432,000

15,358,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Municipal bonds

228,506,000

232,016,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Asset-backed securities

9,334,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Mortgage-backed securities

24,250,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 2 | Common stock

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3

146,781,000

120,064,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Commingled funds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | International equity funds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Private equity investments

81,123,000

62,696,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Real estate

65,658,000

57,368,000

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Government securities

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | U.S. corporate bonds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | International corporate bonds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Municipal bonds

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Asset-backed securities

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Mortgage-backed securities

Nuclear Decommissioning Fund | Fair Value Measured on a Recurring Basis | Fair Value | Level 3 | Common stock