Supplementary Financial Information (Narrative) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2021 USD ($) customer	Dec. 31, 2020 USD ($) customer	Dec. 31, 2019 USD ($)
Supplemental Financial Information [Line Items]
Face value of life insurance policies	$ 198,000	$ 181,000
Net cash surrender values	$ 99,000	$ 97,000
Depreciation expense as percentage of average depreciable property	2.70%	2.70%	2.70%
Aggregate amortization expenses	$ 50,000	$ 62,000	$ 52,000
Goodwill	$ 4,740,000	$ 4,740,000
Land Easements [Member]
Supplemental Financial Information [Line Items]
Weighted average remaining useful life	83 years
Capitalized Software [Member]
Supplemental Financial Information [Line Items]
Weighted average remaining useful life	10 years
Customer Concentration Risk [Member] \| Trade Accounts Receivable [Member]
Supplemental Financial Information [Line Items]
Number of largest customers \| customer	2	2
Customer Concentration Risk [Member] \| Trade Accounts Receivable [Member] \| REP Subsidiary One [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	22.00%	21.00%
Customer Concentration Risk [Member] \| Trade Accounts Receivable [Member] \| REP Subsidiary Two [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	21.00%	15.00%

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Number of largest customers.

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Supplemental Financial Information [Line Items]

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Face value (death benefits) of the life insurance policies underlying the life settlement contracts accounted for under the fair value method.

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