Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
OPERATING ACTIVITIES
Net income	$ 2,838	$ 2,576
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,756	1,584
Deferred income taxes	426	906
Long-term casualty and environmental liabilities, net	(63)	(33)
Other, net	(133)	(98)
Changes in current assets and liabilities:
Accounts receivable, net	(99)	(75)
Materials and supplies	18	35
Other current assets	11	(288)
Accounts payable and other current liabilities	14	392
Net cash provided by operating activities	4,768	4,999
INVESTING ACTIVITIES
Capital expenditures excluding equipment	(2,107)	(2,392)
Acquisition of equipment	(280)	(493)
Purchases of investments and investments in time deposits	(9)	(5)
Proceeds from sales of investments and maturities of time deposits	25	24
Other, net	(204)	(308)
Net cash used for investing activities	(2,575)	(3,174)
FINANCING ACTIVITIES
Proceeds from issuance of long-term debt	1,250	750
Payments on long-term debt	(710)	(266)
Cash distributions	(2,625)	(1,750)
Other, net	(20)	(13)
Net cash used for financing activities	(2,105)	(1,279)
Increase (decrease) in cash and cash equivalents	88	546
Cash and cash equivalents:
Beginning of period	3,218	2,329
End of period	3,306	2,875
SUPPLEMENTAL CASH FLOW INFORMATION
Interest paid, net of amounts capitalized	833	804
Capital investments accrued but not yet paid	147	121
Income taxes paid, net of refunds	$ 1,193	$ 297