Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
OPERATING ACTIVITIES
Net income	$ 2,008	$ 1,640
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	985	1,038
Deferred income taxes	285	77
Long-term casualty and environmental liabilities, net	(17)	(21)
Other, net	(24)	(242)
Changes in current assets and liabilities:
Accounts receivable, net	107	(23)
Materials and supplies	(57)	(31)
Other current assets	(108)	(97)
Accounts payable and other current liabilities	181	411
Net cash provided by operating activities	3,360	2,752
INVESTING ACTIVITIES
Capital expenditures excluding equipment	(1,952)	(1,529)
Acquisition of equipment	(522)	(628)
Purchases of investments	(123)	0
Other, net	(79)	(40)
Net cash used for investing activities	(2,676)	(2,197)
FINANCING ACTIVITIES
Proceeds from issuance of long-term debt	2,000	1,500
Payments on long-term debt	(321)	(589)
Cash distributions	(2,000)	(1,750)
Other, net	(19)	(15)
Net cash provided by financing activities	(340)	(854)
Increase in cash and cash equivalents	344	(299)
Cash and cash equivalents:
Beginning of period	2,384	2,225
End of period	2,728	1,926
SUPPLEMENTAL CASH FLOW INFORMATION
Interest paid, net of amounts capitalized	460	425
Capital investments accrued but not yet paid	214	196
Income taxes paid, net of refunds	$ 548	$ 496