Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities:
Net income	$ 21	$ 1,307	$ 945
Less: Income (loss) from discontinued operations	(3)	4	(7)
Income from continuing operations	24	1,303	952
Adjustments to reconcile to net cash provided by operating activities:
Depreciation, decommissioning and amortization	1,737	1,522	1,418
Regulatory impacts of net nuclear decommissioning trust earnings	146	189	158
Other amortization	152	118	120
Asset impairments, lease terminations and other	1,759	47	888
Stock-based compensation	30	30	22
Equity in income from unconsolidated affiliates	(86)	(106)	(42)
Distributions from unconsolidated affiliates	82	92	31
Deferred income taxes and investment tax credits	(188)	1,139	(1,457)
Income from leveraged leases	(5)	(5)	(14)
Proceeds from U.S. treasury grants	388	92	0
Changes in operating assets and liabilities:
Receivables	19	(155)	80
Inventory	(56)	(49)	20
Margin and collateral deposits - net of collateral received	25	63	30
Prepaid taxes	302	(357)	178
Other current assets	(85)	(24)	(45)
Rent payments in excess of levelized rent expense	(136)	(149)	(160)
Accounts payable	56	(3)	152
Accrued taxes	0	(135)	(402)
Other current liabilities	(33)	13	31
Derivative assets and liabilities - net	383	(44)	(581)
Regulatory assets and liabilities - net	(1,080)	278	1,457
Other assets	(120)	(71)	62
Other liabilities	595	(315)	154
Operating cash flows from discontinued operations	(3)	4	(7)
Net cash provided by operating activities	3,906	3,477	3,045
Cash flows from financing activities:
Long-term debt issued	1,376	1,936	939
Long-term debt issuance costs	(35)	(38)	(25)
Long-term debt repaid	(67)	(396)	(1,044)
Bonds purchased	(86)	0	(219)
Preference stock issued - net	123	0	0
Short-term debt financing - net	389	30	(2,058)
Borrowing held in escrow pending completion of project construction	(97)	0	0
Settlements of stock-based compensation - net	(20)	(16)	(3)
Cash contributions from noncontrolling interests	0	0	2
Dividends and distributions to noncontrolling interests	(59)	(52)	(117)
Dividends paid	(417)	(411)	(404)
Net cash provided (used) by financing activities	1,107	1,053	(2,929)
Cash flows from investing activities:
Capital expenditures	(4,808)	(4,543)	(3,282)
Purchase of interest in acquired companies	(3)	(4)	(22)
Proceeds from termination of leases	0	0	1,420
Proceeds from sale of nuclear decommissioning trust investments	2,773	1,432	2,217
Purchases of nuclear decommissioning trust investments and other	(2,940)	(1,651)	(2,416)
Proceeds from partnerships and unconsolidated subsidiaries, net of investment	41	44	11
Investments in other assets	4	(1)	(287)
Effect of consolidation and deconsolidation of variable interest entities	0	(91)	0
Net cash used by investing activities	(4,933)	(4,814)	(2,359)
Net increase (decrease) in cash and cash equivalents	80	(284)	(2,243)
Cash and cash equivalents, beginning of year	1,389	1,673	3,916
Cash and cash equivalents, end of year	$ 1,469	$ 1,389	$ 1,673