Consolidated Statements of Changes in Total Equity (USD $) In Millions, except Share data, unless otherwise specified	Total USD ($)	PEC USD ($)	PEF USD ($)	Common Stock Outstanding - Shares	Common Stock Outstanding - Shares PEC	Common Stock Outstanding - Shares PEF	Common Stock Outstanding - Amount USD ($)	Common Stock Outstanding - Amount PEC USD ($)	Common Stock Outstanding - Amount PEF USD ($)	Unearned ESOP Shares USD ($)	Unearned ESOP Shares PEC USD ($)	Accumulated Other Comprehensive (Loss) Income USD ($)	Accumulated Other Comprehensive (Loss) Income PEC USD ($)	Accumulated Other Comprehensive (Loss) Income PEF USD ($)	Retained Earnings USD ($)	Retained Earnings PEC USD ($)	Retained Earnings PEF USD ($)	Noncontrolling Interests USD ($)	Noncontrolling Interests PEC USD ($)
Beginning balance at Dec. 31, 2008	$ 8,693	$ 4,305	$ 3,399				$ 6,206	$ 2,083	$ 1,116	$ (25)	$ (25)	$ (116)	$ (35)	$ (1)	$ 2,622	$ 2,278	$ 2,284	$ 6	$ 4
Beginning balances - shares at Dec. 31, 2008				264,000,000	160,000,000	100
Issuance of shares	17,500,000			17,000,000
Net income	757	514	462												757	516	462	0	(2)
Other comprehensive (loss) income	29	8	4									29	8	4
Issuance of shares	623						623
Allocation of ESOP shares	21	23					8	10		13	13
Stock-based compensation expense	36	15	8				36	15	8
Contributions from parent			620						620
Dividends paid to parent		(200)														(200)
Dividends	(704)														(704)
Preferred stock dividends at stated rates		(3)	(2)													(3)	(2)
Distributions to noncontrolling interests	(1)																	(1)
Tax dividend		(3)	(1)													(3)	(1)
Other	1	1																1	1
Notes To Reconciliation Of Total Equity [Abstract]
Dividends declared per common share	$ 2.480
Net income	761	514	462
Net income attributable to preferred shareholders of subsidiaries excluded from reconciliation of total equity	4
Ending balance at Dec. 31, 2009	9,455	4,660	4,490				6,873	2,108	1,744	(12)	(12)	(87)	(27)	3	2,675	2,588	2,743	6	3
Ending balance - shares at Dec. 31, 2009				281,000,000	160,000,000	100
Issuance of shares	12,200,000			12,000,000
Cumulative effect of change in accounting principle	(2)	(2)																(2)	(2)
Net income	859	602	453												856	603	453	3	(1)
Other comprehensive (loss) income	(38)	(6)	(7)									(38)	(6)	(7)
Issuance of shares	434						434
Allocation of ESOP shares	21	22					9	10		12	12
Stock-based compensation expense	27	12	6				27	12	6
Dividends paid to parent		(100)	(50)													(100)	(50)
Dividends	(726)														(726)
Preferred stock dividends at stated rates		(3)	(2)													(3)	(2)
Distributions to noncontrolling interests	(2)																	(2)
Tax dividend		(5)														(5)
Other	(1)																	(1)
Notes To Reconciliation Of Total Equity [Abstract]
Dividends declared per common share	$ 2.480
Net income	863	602	453
Net income attributable to preferred shareholders of subsidiaries excluded from reconciliation of total equity	4
Ending balance at Dec. 31, 2010	10,027	5,180	4,890				7,343	2,130	1,750	0		(125)	(33)	(4)	2,805	3,083	3,144	4
Ending balance - shares at Dec. 31, 2010	293,000,000	160,000,000	100	293,000,000	160,000,000	100
Issuance of shares	2,000,000			2,000,000
Net income	578	516	314												575	516	314	3
Other comprehensive (loss) income	(40)	(38)	(23)									(40)	(38)	(23)
Issuance of shares	53						53
Allocation of ESOP shares	0						0			0
Stock-based compensation expense	38	18	7				38	18	7
Dividends paid to parent		(585)	(510)													(585)	(510)
Dividends	(628)														(628)
Preferred stock dividends at stated rates		(3)	(2)													(3)	(2)
Distributions to noncontrolling interests	(3)																	(3)
Tax dividend			(1)														(1)
Other	0																	0
Notes To Reconciliation Of Total Equity [Abstract]
Dividends declared per common share	$ 2.119
Net income	582	516	314
Net income attributable to preferred shareholders of subsidiaries excluded from reconciliation of total equity	4
Ending balance at Dec. 31, 2011	$ 10,025	$ 5,088	$ 4,675				$ 7,434	$ 2,148	$ 1,757	$ 0		$ (165)	$ (71)	$ (27)	$ 2,752	$ 3,011	$ 2,945	$ 4
Ending balance - shares at Dec. 31, 2011	295,000,000	160,000,000	100	295,000,000	160,000,000	100