Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021		Jun. 30, 2020
Cash flows from operating activities:
Net earnings (loss)	$ 40,265		$ (23,290)
Adjustments to reconcile net earnings to operating cash flows:
Investment (gains) losses	(32,384)		29,593
Depreciation and amortization	5,345		5,109
Other, including asset impairment charges	33		10,520
Changes in operating assets and liabilities:
Losses and loss adjustment expenses	2,357		2,140
Deferred charges reinsurance assumed	473		554
Unearned premiums	2,375		1,268
Receivables and originated loans	(4,825)		(1,885)
Other assets	(909)		(760)
Other liabilities	(664)		(298)
Income taxes	7,493		(5,485)
Net cash flows from operating activities	19,559		17,466
Cash flows from investing activities:
Purchases of equity securities	(3,589)		(4,800)
Sales of equity securities	8,596		15,743
Purchases of U.S. Treasury Bills and fixed maturity securities	(99,731)		(113,169)
Sales of U.S. Treasury Bills and fixed maturity securities	10,814		12,689
Redemptions and maturities of U.S. Treasury Bills and fixed maturity securities	77,541		54,422
Purchases of loans and finance receivables	(56)		(608)
Collections of loans and finance receivables	218		156
Acquisitions of businesses, net of cash acquired	(104)		(82)
Purchases of property, plant and equipment and equipment held for lease	(5,663)		(6,187)
Other	541		(715)
Net cash flows from investing activities	(11,433)		(42,551)
Cash flows from financing activities:
Changes in short term borrowings, net	(65)		(1,166)
Acquisition of treasury stock	(12,560)		(6,739)
Other	(339)		(214)
Net cash flows from financing activities	(13,578)		(2,820)
Effects of foreign currency exchange rate changes	(112)		(140)
Increase (decrease) in cash and cash equivalents and restricted cash	(5,564)		(28,045)
Cash and cash equivalents and restricted cash at beginning of year*	48,396		64,632
Cash and cash equivalents and restricted cash at end of second quarter*	42,832		36,587
Restricted cash, included in other assets at beginning of year	406		457
Restricted cash, included in other assets at end of second quarter	$ 534		$ 513
Restricted Cash and Cash Equivalents, Asset, Statement of Financial Position [Extensible List]	Other		Other
Insurance and Other [Member]
Cash flows from financing activities:
Proceeds from borrowings	$ 2,949		$ 3,428
Repayments of borrowings	(2,481)		(2,092)
Cash and cash equivalents at beginning of year	44,714	[1]	61,151
Cash and cash equivalents at end of second quarter	38,924	[1]	32,318
Railroad, Utilities and Energy [Member]
Cash flows from financing activities:
Proceeds from borrowings	1,464		6,254
Repayments of borrowings	(2,546)		(2,291)
Cash and cash equivalents at beginning of year	3,276	[1]	3,024
Cash and cash equivalents at end of second quarter	$ 3,374	[1]	$ 3,756

[1] Includes U.S. Treasury Bills with maturities of three months or less when purchased of $16.6 billion at June 30, 2021 and $23.2 billion at December 31, 2020.