Equity - Reconciliation of Total Equity (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Beginning balance			$ 10,027	$ 9,455
Cumulative effect of change in accounting principle			0	(2)
Net income			653	732
Other comprehensive loss	(65)	(33)	(82)	(77)
Issuance of shares through offerings and stock-based compensation plans (See Note 5D)			70	461
Dividends declared			(550)	(543)
Distributions to noncontrolling interests			(3)	(2)
Other				0
Ending balance	10,115	10,024	10,115	10,024
Notes To Reconciliation Of Total Equity [Details]
Net income	293	365	656	735
Net income attributable to preferred shareholders of subsidiaries excluded from reconciliation of total equity			3	3
Total Common Stock Equity
Beginning balance			10,023	9,449
Cumulative effect of change in accounting principle			0	0
Net income			651	731
Other comprehensive loss			(82)	(77)
Issuance of shares through offerings and stock-based compensation plans (See Note 5D)			70	461
Dividends declared			(550)	(543)
Distributions to noncontrolling interests			0	0
Other				0
Ending balance	10,112	10,021	10,112	10,021
Noncontrolling Interests
Beginning balance			4	6
Cumulative effect of change in accounting principle			0	(2)
Net income			2	1
Other comprehensive loss			0	0
Issuance of shares through offerings and stock-based compensation plans (See Note 5D)			0	0
Dividends declared			0	0
Distributions to noncontrolling interests			(3)	(2)
Other				0
Ending balance	$ 3	$ 3	$ 3	$ 3