Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 1,718	$ 1,960
Accounts receivable, net	1,127	1,150
Materials and supplies	777	739
Current portion of deferred income taxes	229	295
Other current assets	169	121
Total current assets	4,020	4,265
Property and equipment, net of accumulated depreciation of $1,279 and $1,056, respectively	49,103	48,047
Goodwill	14,803	14,803
Intangible assets, net	1,267	1,420
Other assets	1,900	1,845
Total assets	71,093	70,380
Current liabilities:
Accounts payable and other current liabilities	3,022	3,143
Long-term debt due within one year	517	526
Total current liabilities	3,539	3,669
Deferred income taxes	15,861	15,637
Long-term debt	13,211	12,139
Intangible liabilities, net	1,355	1,496
Casualty and environmental liabilities	849	905
Pension and retiree health and welfare liability	732	769
Other liabilities	1,054	1,016
Total liabilities	36,601	35,631
Commitments and contingencies (see Notes 2, 6 and 7)
Equity:
Member's Equity	34,705	34,952
Accumulated other comprehensive loss	(213)	(203)
Total equity	34,492	34,749
Total liabilities and equity	$ 71,093	$ 70,380