Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
OPERATING ACTIVITIES
Net income	$ 1,253	$ 1,145
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	591	571
Deferred income taxes	115	102
Long-term casualty and environmental liabilities, net	1	(5)
Other, net	(254)	(90)
Changes in current assets and liabilities:
Accounts receivable, net	95	5
Materials and supplies	(20)	(4)
Other current assets	(149)	(91)
Accounts payable and other current liabilities	277	(13)
Net cash provided by operating activities	1,909	1,620
INVESTING ACTIVITIES
Capital expenditures excluding equipment	(569)	(519)
Acquisition of equipment	(50)	(46)
Purchases of investments and investments in time deposits	(5)	(8)
Proceeds from sales of investments and maturities of time deposits	3	7
Other, net	(71)	(94)
Net cash used for investing activities	(692)	(660)
FINANCING ACTIVITIES
Proceeds from issuance of long-term debt	0	750
Payments on long-term debt	(11)	(671)
Cash distributions	(1,200)	(1,100)
Other, net	0	(8)
Net cash used for financing activities	(1,211)	(1,029)
Increase in cash and cash equivalents	6	(69)
Cash and cash equivalents:
Beginning of period	1,985	1,975
End of period	1,991	1,906
SUPPLEMENTAL CASH FLOW INFORMATION
Interest paid, net of amounts capitalized	283	310
Capital investments accrued but not yet paid	116	86
Income taxes paid, net of refunds	13	7
Non-cash asset financing	$ 4	$ 0