Supplemental cash flow information (Detail) (USD $) In Millions	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Cash paid during the period for:
Income taxes	$ 802	$ 2,319
Insurance and Other [Member]
Cash paid during the period for:
Interest	115	80
Railroad, Utilities and Energy [Member]
Cash paid during the period for:
Interest	904	790
Finance and Financial Products [Member]
Cash paid during the period for:
Interest	340	361
Burlington Northern Santa Fe [Member]
Non-cash investing and financing activities:
Liabilities assumed in connection with acquisition		30,968
Common stock issued in connection with acquisition		10,577
Wesco Financial Corporation [Member]
Non-cash investing and financing activities:
Common stock issued in connection with acquisition	$ 245

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

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The amount of cash paid for interest during the period net of cash paid for interest that is capitalized.

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- Definition

The total amount of [all] liabilities that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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