Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net earnings	$ 12,697	$ 18,072
Adjustments to reconcile net earnings to operating cash flows:
Investment gains/losses	(1,262)	(5,643)
Depreciation and amortization	6,835	6,605
Other	1,110	(47)
Changes in operating assets and liabilities:
Losses and loss adjustment expenses	22,615	2,615
Deferred charges reinsurance assumed	(5,525)	182
Unearned premiums	2,253	1,906
Receivables and originated loans	(2,890)	(3,445)
Derivative contract assets and liabilities	(704)	137
Income taxes	2,593	3,601
Other	(225)	1,114
Net cash flows from operating activities	37,497	25,097
Cash flows from investing activities:
Purchases of U.S. Treasury Bills and fixed maturity securities	(106,597)	(79,326)
Purchases of equity securities	(14,936)	(5,185)
Sales of U.S. Treasury Bills and fixed maturity securities	35,143	8,430
Redemptions and maturities of U.S. Treasury Bills and fixed maturity securities	65,666	21,725
Sales and redemptions of equity securities	10,572	19,989
Purchases of loans and finance receivables	(1,392)	(224)
Collections of loans and finance receivables	1,599	271
Acquisitions of businesses, net of cash acquired	(2,640)	(30,815)
Purchases of property, plant and equipment	(8,411)	(9,429)
Other	(198)	(611)
Net cash flows from investing activities	(21,194)	(75,175)
Cash flows from financing activities:
Changes in short term borrowings, net	122	888
Other financing activities	(108)	(31)
Net cash flows from financing activities	(1,867)	12,196
Effects of foreign currency exchange rate changes	222	(10)
Increase (decrease) in cash and cash equivalents	14,658	(37,892)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	28,048	67,161
Cash and cash equivalents at September 30	42,706	29,269
Insurance and Other [Member]
Adjustments to reconcile net earnings to operating cash flows:
Investment gains/losses	(1,056)	(3,221)
Cash flows from financing activities:
Proceeds from borrowings	1,321	9,385
Repayments of borrowings	(1,763)	(1,921)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	23,581	56,612
Cash and cash equivalents at September 30	35,247	21,778
Railroad, Utilities and Energy [Member]
Cash flows from financing activities:
Proceeds from borrowings	2,812	2,234
Repayments of borrowings	(1,944)	(1,879)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	3,939	3,437
Cash and cash equivalents at September 30	4,448	3,893
Finance and Financial Products [Member]
Adjustments to reconcile net earnings to operating cash flows:
Investment gains/losses	(206)	(2,422)
Cash flows from financing activities:
Proceeds from borrowings	1,298	4,740
Repayments of borrowings	(3,605)	(1,220)
Cash and cash equivalents:
Cash and cash equivalents at beginning of year	528	7,112
Cash and cash equivalents at September 30	$ 3,011	$ 3,598