Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net earnings	$ 10,651	$ 7,555
Adjustments to reconcile net earnings to operating cash flows:
Investment (gains) losses and other-than-temporary impairment losses	(936)	(974)
Depreciation	3,814	3,418
Other	641	374
Changes in operating assets and liabilities before business acquisitions:
Losses and loss adjustment expenses	(435)	3,478
Deferred charges reinsurance assumed	204	(525)
Unearned premiums	2,136	1,599
Receivables and originated loans	(1,759)	(1,847)
Derivative contract assets and liabilities	(104)	2,222
Income taxes	724	1,024
Other assets	(316)	(1,427)
Other liabilities	1,540	1,085
Net cash flows from operating activities	16,160	15,982
Cash flows from investing activities:
Purchases of fixed maturity securities	(6,684)	(6,122)
Purchases of equity securities	(6,454)	(11,351)
Purchases of other investments		(5,000)
Sales of fixed maturity securities	2,607	1,612
Redemptions and maturities of fixed maturity securities	4,646	5,419
Sales of equity securities	7,006	885
Redemptions of other investments		9,345
Purchases of loans and finance receivables	(546)	(1,615)
Collections on loans and finance receivables	1,098	2,683
Acquisitions of businesses, net of cash acquired	(1,831)	(7,984)
Purchases of property, plant and equipment	(7,193)	(5,673)
Other	(115)	15
Net cash flows from investing activities	(7,466)	(17,786)
Cash flows from financing activities:
Change in short term borrowings, net	(989)	(552)
Acquisitions of noncontrolling interests and other	(76)	(1,810)
Net cash flows from financing activities	1,679	(1,758)
Effects of foreign currency exchange rate changes	104	111
Increase (decrease) in cash and cash equivalents	10,477	(3,451)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	37,299	38,227
Cash and cash equivalents at end of first nine months	47,776	34,776
Insurance and Other [Member]
Adjustments to reconcile net earnings to operating cash flows:
Depreciation	1,443	1,191
Cash flows from financing activities:
Proceeds from borrowings	1,796	2,063
Repayments of borrowings	(1,962)	(2,272)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	33,513	34,767
Cash and cash equivalents at end of first nine months	41,820	30,587
Railroad, Utilities and Energy [Member]
Adjustments to reconcile net earnings to operating cash flows:
Depreciation	2,235	2,093
Cash flows from financing activities:
Proceeds from borrowings	4,699	2,290
Repayments of borrowings	(1,137)	(1,158)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	2,246	2,557
Cash and cash equivalents at end of first nine months	4,119	2,965
Finance and Financial Products [Member]
Cash flows from financing activities:
Proceeds from borrowings	2,357	1,528
Repayments of borrowings	(3,009)	(1,847)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	1,540	903
Cash and cash equivalents at end of first nine months	$ 1,837	$ 1,224