Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024		Dec. 31, 2023		Dec. 31, 2022
Cash flows from operating activities:
Net earnings (loss)	$ 89,561		$ 97,147		$ (21,998)
Adjustments to reconcile net earnings (loss) to operating cash flows:
Investment (gains) losses	(52,799)		(74,855)		67,899
Depreciation and amortization	12,855		12,486		10,899
Discount accretion on investments, principally U.S. Treasury Bills	(11,349)		(5,510)		(1,132)
Other	(892)		(513)		(3,074)
Changes in operating assets and liabilities:
Unpaid losses and loss adjustment expenses	2,173		2,628		4,057
Deferred charges - retroactive reinsurance	698		375		769
Unearned premiums	376		1,854		1,861
Receivables and originated loans	626		(1,949)		(5,621)
Inventories	591		1,426		(4,779)
Other assets	(797)		(1,328)		(378)
Other liabilities	(2,288)		2,570		1,719
Income taxes	(8,163)		14,865		(12,872)
Net cash flows from operating activities	30,592		49,196		37,350
Cash flows from investing activities:
Purchases of equity securities	(9,237)		(16,462)		(67,930)
Sales of equity securities	143,359		40,631		33,664
Purchases of U.S. Treasury Bills and fixed maturity securities	(526,842)		(235,007)		(183,922)
Sales of U.S. Treasury Bills and fixed maturity securities	48,462		52,302		90,088
Redemptions and maturities of U.S. Treasury Bills and fixed maturity securities	353,538		153,201		66,318
Acquisitions of businesses, net of cash acquired	(396)		(8,604)		(10,594)
Purchases of property, plant and equipment and equipment held for lease	(18,976)		(19,409)		(15,464)
Other	(195)		685		239
Net cash flows from investing activities	(10,287)		(32,663)		(87,601)
Cash flows from financing activities:
Changes in short term borrowings, net	(3,059)		2,407		(596)
Acquisitions of treasury stock	(2,918)		(9,171)		(7,854)
Other, principally transactions with noncontrolling interests	(5,622)		(4,147)		(1,979)
Net cash flows from financing activities	(10,360)		(14,405)		(1,662)
Effects of foreign currency exchange rate changes	(212)		116		(394)
Increase (decrease) in cash and cash equivalents and restricted cash	9,733		2,244		(52,307)
Cash and cash equivalents and restricted cash at the beginning of the year	38,643		36,399		88,706
Cash and cash equivalents and restricted cash at the end of the year	48,376		38,643		36,399
Restricted cash, included in other assets at end of year	$ 647		$ 621		$ 588
Restricted Cash and Cash Equivalents, Statement of Financial Position [Extensible Enumeration]	Other		Other		Other
Insurance and Other [Member]
Cash flows from financing activities:
Proceeds from borrowings	$ 5,528		$ 2,133		$ 7,822
Repayments of borrowings	(7,796)		(6,027)		(1,502)
Cash and cash equivalents at the end of the year	44,333	[1]	34,268	[1]	32,260
Railroad, Utilities and Energy [Member]
Cash flows from financing activities:
Proceeds from borrowings	7,658		5,684		4,873
Repayments of borrowings	(4,151)		(5,284)		(2,426)
Cash and cash equivalents at the end of the year	$ 3,396	[1]	$ 3,754	[1]	$ 3,551

[1] Includes U.S. Treasury Bills with maturities of three months or less when purchased of $14.4 billion at December 31, 2024 and $4.8 billion at December 31, 2023.