Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Deferred Taxes
Balance beginning	$ (397)	$ (96)	$ (416)	$ (95)
Changes in value	(3)	6	1	5
Amounts reclassified to earnings	7	0	22	0
Balance ending	(393)	(90)	(393)	(90)
Total
Balance beginning	7,705	3,964	6,896	5,029
Changes in value	14	(20)	(3)	(21)
Amounts reclassified to earnings	(26)	0	(81)	(1)
Balance ending	8,853	4,898	8,853	4,898
Accumulated Other Comprehensive Income (Loss)
Total
Balance beginning	103	(944)	175	(942)
Balance ending	91	(964)	91	(964)
Deferred income tax expense			285	285
Pension and Other Postretirement Liabilities
Before Tax
Balance beginning	539	(834)	626	(847)
Changes in value	7	(1)	(10)	13
Amounts reclassified to earnings	(33)	0	(103)	(1)
Balance ending	513	(835)	513	(835)
Investments and Other
Before Tax
Balance beginning	(39)	(14)	(35)	0
Changes in value	10	(25)	6	(39)
Amounts reclassified to earnings	0	0	0	0
Balance ending	$ (29)	$ (39)	$ (29)	$ (39)

AOCI Attributable To Parent, Before Tax [Roll Forward]

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AOCI Attributable To Parent, Tax [Roll Forward]

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount before tax of increase (decrease) in accumulated equity from transactions and other events and circumstances from non-owner sources, attributable to parent. Excludes net income (loss), and accumulated changes in equity from transactions resulting from investments by owners (distributions to owners).

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Amount of tax expense (benefit) allocated to accumulated other comprehensive income (loss) attributable to parent.

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Amount of deferred income tax expense (benefit) and income tax credits.

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Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) before reclassification adjustment from accumulated other comprehensive income (loss).

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Amount before tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss).

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Amount of equity (deficit) attributable to parent. Excludes temporary equity and equity attributable to noncontrolling interest.

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