Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 3,015	$ 2,384
Accounts receivable, net	1,336	1,386
Materials and supplies	820	795
Current portion of deferred income taxes	209	355
Other current assets	226	232
Total current assets	5,606	5,152
Property and equipment, net of accumulated depreciation of $4,127 and $3,550, respectively	56,513	55,806
Goodwill	14,819	14,819
Intangible assets, net	481	512
Other assets	1,943	1,914
Total assets	79,362	78,203
Current liabilities:
Accounts payable and other current liabilities	3,428	3,435
Long-term debt due within one year	295	366
Total current liabilities	3,723	3,801
Long-term debt	20,171	18,914
Deferred income taxes	17,998	18,001
Intangible liabilities, net	748	782
Casualty and environmental liabilities	628	639
Pension and retiree health and welfare liability	383	385
Other liabilities	933	947
Total liabilities	44,584	43,469
Commitments and contingencies (see Notes 6 and 7)
Equity:
Member's equity	34,781	34,736
Accumulated other comprehensive income	(3)	(2)
Total equity	34,778	34,734
Total liabilities and equity	$ 79,362	$ 78,203