Investments In Debt And Equity Securities (Tables)

3 Months Ended

Mar. 31, 2012

Investments In Debt And Equity Securities [Abstract]

Available-For-Sale Investments

	March 31, 2012								December 31, 2011
	Gross Unrealized Holding Gains		Gross Unrealized Holding Losses			Estimated Fair Value			Gross Unrealized Holding Gains	Gross Unrealized Holding Losses			Estimated Fair Value
	(in millions)
Duke Energy Carolinas NDTF:
Equity Securities	$	591	$	(7	)	$	1,518	$443		$	(16	)	$	1,337
Corporate Debt Securities		8		(1	)		222	8			(2	)		205
Municipal Bonds		2		—			51	2			—			51
U.S. Government Bonds		11		—			285	16			—			306
Other Debt Securities		4		(1	)		171	4			(4	)		161
Total Duke Energy Carolinas NDTF	$	616	$	(9	)	$	2,247	$473		$	(22	)	$	2,060
Duke Energy Indiana Grantor Trust:
Equity Securities	$	10	$	—		$	52	$5		$	(1	)	$	46
Municipal Bonds		—		—			28	1			—			28
Total Duke Energy Indiana Grantor Trust	$	10	$	—		$	80	$6		$	(1	)	$	74
Other Investments:
Equity Securities	$	1	$	—		$	20	$—		$	(1	)		14
Corporate Debt Securities		2		—			299	1			(1	)		241
Municipal Bonds		—		—			—	—			—			—
U.S. Government Bonds		1		(1	)		57	1			—			21
Other Debt Securities		1		—			83	2			—			68
Auction Rate Securities(a)		—		(17	)		72	—			(17	)		71
Total Other Investments	$	5	$	(18	)	$	531	$4		$	(19	)	$	415
Total Duke Energy Investments	$	631	$	(27	)	$	2,858	$483		$	(42	)	$	2,549

(a) At both March 31, 2012 and December 31, 2011, $12 million of these securities were held by Duke Energy Carolinas. Gross unrealized holding gains on these securities held by Duke Energy Carolinas were insignificant at both March 31, 2012 and December 31, 2011. Gross unrealized holding losses on these securities held by Duke Energy Carolinas were $3 million at both March 31, 2012 and December 31, 2011.

Summarizes The Maturity Date For Debt Securities

	< 1 Year		1-5 Years		6-10 Years		Thereafter
	(in millions)
Duke Energy(a)	$	168	$	404	$	223	$	401
Duke Energy Carolinas(a)	$	75	$	150	$	183	$	321
Duke Energy Indiana	$	—	$	20	$	6	$	2

Unrealized Losses Of Available-For-Sale Debt And Equity Securities In A Continuous Loss Position

	March 31, 2012								December 31, 2011
	Fair Value		Unrealized Loss Position >12 months			Unrealized Loss Position <12 months			Fair Value		Unrealized Loss Position >12 months			Unrealized Loss Position <12 months
	(in millions)
Duke Energy Carolinas NDTF:
Equity Securities	$	54	$	(4	)	$	(3	)	$	111	$	(4	)	$	(12	)
Corporate Debt Securities		48		—			(1	)		57		(1	)		(1	)
Municipal Bonds		13		—			—			—		—			—
U.S. Government Bonds		73		—			—			8		—			—
Other Debt Securities		36		—			(1	)		113		(1	)		(3	)
Total Duke Energy Carolinas NDTF	$	224	$	(4	)	$	(5	)	$	289	$	(6	)	$	(16	)
Duke Energy Indiana Grantor Trust:
Equity Securities	$	—	$	—		$	—		$	8	$	—		$	(1	)
Municipal Bonds		9		—			—			3		—			—
Total Indiana Grantor Trust	$	9	$	—		$	—		$	11	$	—		$	(1	)
Other Investments:
Equity Securities	$	6	$	—		$	(1	)	$	4	$	(1	)	$	—
Corporate Debt Securities		254		—			—			201		(1	)		—
Municipal Bonds		—		—			—			—		—			—
U.S. Government Bonds		31		—			—			—		—			—
Other Debt Securities		16		—			—			8		—			—
Auction Rate Securities(a)		72		(17	)		—			71		(17	)		—
Total Other Investments	$	379	$	(17	)	$	(1	)	$	284	$	(19	)	$	—
Total Duke Energy Investments	$	612	$	(21	)	$	(6	)	$	584	$	(25	)	$	(17	)

(a) At both March 31, 2012 and December 31, 2011, $12 million of these securities were held by Duke Energy Carolinas. The gross unrealized losses on these securities held by Duke Energy Carolinas which were in an unrealized loss position greater than 12 months were $3 million at both March 31, 2012 and December 31, 2011. The gross unrealized losses on these securities held by Duke Energy Carolinas which were in an unrealized loss position less than 12 months were insignificant at both March 31, 2012 and December 31, 2011.