Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
OPERATING ACTIVITIES
Net income	$ 1,045	$ 724
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	496	515
Deferred income taxes	143	61
Long-term casualty and environmental liabilities, net	(11)	(9)
Other, net	(63)	(217)
Changes in current assets and liabilities:
Accounts receivable, net	49	(9)
Materials and supplies	(25)	(24)
Other current assets	(82)	(66)
Accounts payable and other current liabilities	178	172
Net cash provided by operating activities	1,730	1,147
INVESTING ACTIVITIES
Capital expenditures excluding equipment	(844)	(645)
Acquisition of equipment	(347)	(273)
Purchases of investments	(45)	0
Other, net	(64)	(96)
Net cash used for investing activities	(1,300)	(1,014)
FINANCING ACTIVITIES
Proceeds from issuance of long-term debt	1,500	1,500
Payments on long-term debt	(283)	(538)
Cash distributions	(1,000)	(750)
Other, net	(16)	(15)
Net cash provided by financing activities	201	197
Increase in cash and cash equivalents	631	330
Cash and cash equivalents:
Beginning of period	2,384	2,225
End of period	3,015	2,555
SUPPLEMENTAL CASH FLOW INFORMATION
Interest paid, net of amounts capitalized	285	277
Capital investments accrued but not yet paid	166	119
Income taxes paid, net of refunds	$ 11	$ 34