Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 2,809	$ 1,794
Accounts receivable, net	1,311	1,168
Materials and supplies	800	800
Current portion of deferred income taxes	250	341
Other current assets	131	77
Total current assets	5,301	4,180
Property and equipment, net of accumulated depreciation of $1,923 and $1,626, respectively	51,659	50,070
Goodwill	14,836	14,836
Intangible assets, net	887	1,114
Other assets	1,896	1,816
Total assets	74,579	72,016
Current liabilities:
Accounts payable and other current liabilities	3,050	3,122
Long-term debt due within one year	655	453
Total current liabilities	3,705	3,575
Deferred income taxes	16,691	16,319
Long-term debt	16,411	14,080
Intangible liabilities, net	1,025	1,214
Pension and retiree health and welfare liability	755	786
Casualty and environmental liabilities	738	750
Other liabilities	1,146	963
Total liabilities	40,471	37,687
Commitments and contingencies (see Notes 6 and 7)
Equity:
Member's Equity	34,345	34,574
Accumulated other comprehensive loss	(237)	(245)
Total equity	34,108	34,329
Total liabilities and equity	$ 74,579	$ 72,016