Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES
Net income	$ 3,793	$ 3,372	$ 2,972
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,973	1,889	1,807
Deferred income taxes	583	660	1,509
Long-term casualty and environmental liabilities, net	(98)	(190)	(43)
Contributions to qualified pension plan	(25)	(36)	(36)
Other, net	(88)	(314)	(249)
Changes in current assets and liabilities:
Accounts receivable, net	(130)	(6)	(219)
Materials and supplies	(35)	(61)	(87)
Other current assets	(6)	14	(15)
Accounts payable and other current liabilities	(205)	105	301
Net cash provided by operating activities	5,762	5,433	5,940
INVESTING ACTIVITIES
Capital expenditures excluding equipment	(2,975)	(2,596)	(2,726)
Acquisition of equipment	(943)	(952)	(763)
Partnership Investment	0	(130)	0
Other, net	55	(158)	33
Net cash used for investing activities	(3,863)	(3,836)	(3,456)
FINANCING ACTIVITIES
Proceeds from issuance of long-term debt	3,000	2,500	1,500
Payments on long-term debt	(440)	(482)	(596)
Cash distributions	4,000	3,750	3,500
Other, net	(28)	(31)	(15)
Net cash used for financing activities	(1,468)	(1,763)	(2,611)
Increase/(decrease) in cash and cash equivalents	431	(166)	(127)
Cash and cash equivalents:
Beginning of period	1,794	1,960	2,087
End of period	2,225	1,794	1,960
SUPPLEMENTAL CASH FLOW INFORMATION
Interest paid, net of amounts capitalized	772	707	666
Capital investments accrued but not yet paid	224	123	190
Income taxes paid, net of refunds	1,752	1,194	(13)
Non-cash asset financing	$ 0	$ 0	$ 1