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Fair Value of Financial Instruments (Equity Investments) (Narrative) (Details) - USD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items] |  |  |
Equity investments, carrying value | $ 220,000,000 | $ 196,000,000 |
Equity investments, adjusted cost basis, amount | 17,000,000 | 18,000,000 |
Equity investments, impairments | $ 0 | 0 | $ 0
Waha JVs [Member] |  |  |
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items] |  |  |
Equity method investment, ownership percentage | 33.00% |  |
Equity investments, carrying value | $ 175,000,000 | $ 174,000,000 |
CCI [Member] |  |  |
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items] |  |  |
Equity investments, adjusted cost basis, amount | $ 15,000,000 |  |
CCI [Member] | Immediate Family Member of Management [Member] |  |  |
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items] |  |  |
Equity investment, ownership percentage | 15.00% |  |
FM Tech [Member] |  |  |
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items] |  |  |
Equity method investment, ownership percentage | 50.00% |  |
Equity investments, carrying value | $ 16,000,000 |  |

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- Definition Amount of impairment loss on investment in equity security without readily determinable fair value. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117539-209714 + Details
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