Consolidated Statements of Cash Flows (Unaudited) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities
Net income	$ 1,436	$ 1,094
Reconciliation of net income to net cash provided by operating activities:
Depreciation	646	617
Deferred income taxes	414	172
Gains and losses on properties and investments	(30)	(38)
Changes in assets and liabilities affecting operations:
Accounts receivable	(222)	(142)
Materials and supplies	(43)	(15)
Other current assets	60	50
Current liabilities other than debt	402	254
Other, net	101	136
Net cash provided by operating activities	2,764	2,128
Cash flows from investing activities
Property additions	(1,433)	(907)
Property sales and other transactions	70	81
Investments, including short-term	(88)	(441)
Investment sales and other transactions	246	261
Net cash used in investing activities	(1,205)	(1,006)
Cash flows from financing activities
Dividends	(432)	(384)
Common stock issued, net	95	59
Purchase and retirement of common stock	(1,611)	(437)
Proceeds from borrowings, net	396	250
Debt repayments	(592)	(477)
Net cash used in financing activities	(2,144)	(989)
Net increase (decrease) in cash and cash equivalents	(585)	133
Cash and cash equivalents
At beginning of year	827	996
At end of period	242	1,129
Supplemental disclosure of cash flow information
Interest (net of amounts capitalized)	296	296
Income taxes (net of refunds)	$ 121	$ 498