Equity - Reconciliation of Total Equity (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Beginning balance			$ 10,027	$ 9,455
Cumulative effect of change in accounting principle (Note 2)			0
Net income			361	368
Other comprehensive loss	(21)	(40)	(17)	(44)
Issuance of shares through offerings and stock-based compensation plans (See Note 5D)			47	443
Dividends declared			(367)	(361)
Distributions to noncontrolling interests			(2)	(2)
Other				0
Ending balance	10,049	9,859	10,049	9,859
Notes To Reconciliation Of Total Equity [Details]
Net income	178	180	363	370
Net income attributable to preferred shareholders of subsidiaries excluded from reconciliation of total equity			2	2
Total Common Stock Equity
Beginning balance			10,023	9,449
Cumulative effect of change in accounting principle (Note 2)			0
Net income			360	370
Other comprehensive loss			(17)	(44)
Issuance of shares through offerings and stock-based compensation plans (See Note 5D)			47	443
Dividends declared			(367)	(361)
Distributions to noncontrolling interests			0	0
Other				0
Ending balance	10,046	9,857	10,046	9,857
Noncontrolling Interests
Beginning balance			4	6
Cumulative effect of change in accounting principle (Note 2)			0
Net income			1	(2)
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			(2)	(2)
Other				0
Ending balance	$ 3	$ 2	$ 3	$ 2