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Investments (Unconsolidated Equity Investments) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Schedule of Equity Method Investments [Line Items] |  |  |
Carrying value | $ 508 | $ 476 | $ 458
Equity (income) / loss | (62) | (61) | (53)
ATC Holdings [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Carrying value | 338 | 331 |
Equity (income) / loss | $ (43) | (47) | (45)
ATC LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Ownership interest | 16.00% |  |
ATC Holdco LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Ownership interest | 20.00% |  |
Non-utility wind farm in Oklahoma [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Ownership interest | 50.00% |  |
Carrying value | $ 99 | 103 |
Equity (income) / loss | (4) | (8) | (5)
Corporate venture investments [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Carrying value | 52 | 31 |
Equity (income) / loss | (13) | (4) | (1)
Other [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Carrying value | 19 | 11 |
Equity (income) / loss | (2) | (2) | (2)
Total [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Carrying value | 508 | 476 |
Equity (income) / loss | $ (62) | $ (61) | $ (53)

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- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 25 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8813-108599 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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