Contingencies and Commitments - Narrative (Detail) - USD ($) $ in Millions		1 Months Ended
Mar. 20, 2022	Jun. 30, 2022
Business Acquisition [Line Items]
Excess consideration paid for acquiring noncontrolling Interest		$ 362
Alleghany Corporation [Member]
Business Acquisition [Line Items]
Acquisition of outstanding shares, value	$ 11,600
Business acquisition, agreement date	Mar. 20, 2022
Greg Abel \| Berkshire Hathaway Energy [Member]
Business Acquisition [Line Items]
Acquisition of outstanding shares, value		$ 870

Amount of other increase (decrease) in additional paid in capital (APIC).

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- Definition

Date when the business acquisition agreement was executed, in YYYY-MM-DD format.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

+ References

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- Definition

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

+ References

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