Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2014
OPERATING ACTIVITIES
Net income	$ 5,219	$ 11,300	$ 3,569
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,317	2,352	2,128
Deferred Income Tax Expense (Benefit), Adjusted	381	(6,435)
Deferred income taxes	379	(6,421)	998
Long-term casualty and environmental liabilities, net	(18)	(85)	(35)
Other, net	(147)	(289)	27
Changes in current assets and liabilities:
Accounts receivable, net	(48)	(177)	(74)
Materials and supplies	10	22	4
Other current assets	(52)	(163)	(129)
Accounts payable and other current liabilities	246	(206)	437
Net cash provided by operating activities	7,908	6,319	6,925
INVESTING ACTIVITIES
Capital expenditures excluding equipment	(2,918)	(2,860)	(3,205)
Acquisition of equipment	(269)	(397)	(614)
Purchases of Investments and investments in time deposits	(27)	(13)	(8)
Proceeds from sales of investments and maturities of time deposits	45	34	27
Other, net	(11)	(247)	(181)
Net cash used for investing activities	(3,180)	(3,483)	(3,981)
FINANCING ACTIVITIES
Proceeds from issuance of long-term debt	1,500	1,250	750
Payments on long-term debt	(746)	(735)	(292)
Cash distributions	(5,450)	(4,575)	(2,500)
Other, net	(22)	(19)	(13)
Net cash used for financing activities	(4,718)	(4,079)	(2,055)
Increase/(decrease) in cash and cash equivalents	10	(1,243)	889
Cash and cash equivalents:
Beginning of period	1,975	3,218	2,329
End of period	1,985	1,975	3,218
SUPPLEMENTAL CASH FLOW INFORMATION
Interest paid, net of amounts capitalized	1,072	1,062	1,016
Capital investments accrued but not yet paid	251	192	305
Income taxes paid, net of refunds	905	1,789	$ 752
Non-cash asset financing	$ 8	$ 0		$ 0