Condensed Financial Information - Statements of Cash Flows (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net earnings attributable to Berkshire Hathaway shareholders	$ 89,795	$ 42,521	$ 81,417
Adjustments to reconcile net earnings to cash flows from operating activities:
Investment gains/losses	(77,576)	(40,905)	(71,123)
Income taxes payable	15,297	7,195	15,181
Other, including asset impairment charges	(3,397)	11,263	(1,254)
Net cash flows from operating activities	39,421	39,773	38,687
Cash flows from investing activities:
Other	297	(3,582)	(1,496)
Net cash flows from investing activities	29,392	(37,757)	(5,621)
Cash flows from financing activities:
Acquisition of treasury stock	(27,061)	(24,706)	(4,850)
Other	(695)	(429)	(497)
Net cash flows from financing activities	(28,508)	(18,344)	730
Other cash flow information:
Income taxes paid	5,412	5,001	5,415
Berkshire Hathaway Inc. (Parent) [Member]
Cash flows from operating activities:
Net earnings attributable to Berkshire Hathaway shareholders	89,795	42,521	81,417
Adjustments to reconcile net earnings to cash flows from operating activities:
Investment gains/losses	(35)	24	125
Undistributed earnings of consolidated subsidiaries	(74,819)	(17,402)	(65,237)
Non-cash dividends from subsidiaries	(2,126)	(8,296)
Income taxes payable	(389)	(72)	(56)
Other, including asset impairment charges	(1,038)	1,100	(693)
Net cash flows from operating activities	11,388	17,875	15,556
Cash flows from investing activities:
Investments in and advances to/from consolidated subsidiaries, net	(174)	(1,947)	60
Purchases of U.S. Treasury Bills	(34,988)	(54,715)	(40,107)
Sales and maturities of U.S. Treasury Bills	57,296	59,035	36,943
Other		11	737
Net cash flows from investing activities	22,134	2,384	(2,367)
Cash flows from financing activities:
Proceeds from borrowings	2,174	2,923	3,967
Repayments of borrowings	(2,167)	(1,151)	(758)
Acquisition of treasury stock	(27,061)	(24,706)	(4,850)
Other			19
Net cash flows from financing activities	(27,054)	(22,934)	(1,622)
Increase (decrease) in cash and cash equivalents	6,468	(2,675)	11,567
Cash and cash equivalents at beginning of year	12,329	15,004	3,437
Cash and cash equivalents at end of year	18,797	12,329	15,004
Other cash flow information:
Income taxes paid	3,403	3,391	3,531
Interest paid	$ 377	$ 359	$ 364