Investments in Marketable Securities (Tables)

3 Months Ended

Jun. 30, 2013

Investments in Marketable Securities [Abstract]

Summary of Investments in Marketable Securities

				June 30, 2013
				Amortized		Unrealized		Unrealized		Fair
(Dollars in millions)				cost		gains		losses		value
Available-for-sale securities:
	Debt instruments:
		U.S. government and agency obligations		$	78	$	1	$	(1)	$	78
		Municipal debt securities			14		1		-		15
		Certificates of deposit			1,836		1		-		1,837
		Commercial paper			355		-		-		355
		Foreign government debt securities			3		-		-		3
		Corporate debt securities			149		4		(4)		149
		Mortgage-backed securities:
			U.S. government agency		78		2		(1)		79
			Non-agency residential		4		1		-		5
			Non-agency commercial		49		1		(2)		48
		Asset-backed securities			19		-		-		19
	Equity instruments:
		Fixed income mutual funds:
			Short-term sector fund		40		3		-		43
			U.S. government sector fund		324		-		(5)		319
			Municipal sector fund		20		1		-		21
			Investment grade corporate sector fund		259		41		-		300
			High-yield sector fund		35		6		-		41
			Real return sector fund		286		-		(16)		270
			Mortgage sector fund		599		-		-		599
			Asset-backed securities sector fund		39		9		-		48
			Emerging market sector fund		64		1		(2)		63
			International sector fund		166		4		-		170
		Equity mutual fund			259		236		-		495
Total investments in marketable securities				$	4,676	$	312	$	(31)	$	4,957

Note 3 – Investments in Marketable Securities (Continued)
					March 31, 2013
				Amortized		Unrealized		Unrealized		Fair
(Dollars in millions)				cost		gains		losses		value
Available-for-sale securities:
	Debt instruments:
		U.S. government and agency obligations		$	101	$	3	$	-	$	104
		Municipal debt securities			14		2		-		16
		Certificates of deposit			2,040		1		-		2,041
		Commercial paper			495		-		-		495
		Foreign government debt securities			3		-		-		3
		Corporate debt securities			122		6		-		128
		Mortgage-backed securities:
			U.S. government agency		83		4		-		87
			Non-agency residential		4		1		-		5
			Non-agency commercial		50		1		-		51
		Asset-backed securities			13		-		-		13
	Equity instruments:
		Fixed income mutual funds:
			Short-term sector fund		40		3		-		43
			U.S. government sector fund		296		16		-		312
			Municipal sector fund		19		3		-		22
			Investment grade corporate sector fund		273		54		-		327
			High-yield sector fund		34		8		-		42
			Real return sector fund		284		9		-		293
			Mortgage sector fund		663		-		(15)		648
			Asset-backed securities sector fund		38		9		-		47
			Emerging market sector fund		63		3		-		66
			International sector fund		163		7		-		170
		Equity mutual fund			259		225		-		484
Total investments in marketable securities				$	5,057	$	355	$	(15)	$	5,397

Summary of the aging of fair value and gross unrealized losses for AFS securities

					Less than 12 months as of
					June 30, 2013				March 31, 2013
					Fair		Unrealized		Fair		Unrealized
(Dollars in millions)					value		losses		value		losses
Available-for-sale securities:
	Debt instruments:
			U.S. government and agency
				obligations	$	35	$	(1)	$	-	$	-
			Corporate debt securities			93		(4)		-		-
			Mortgage backed securities:
				U.S. government agency		38		(1)		-		-
				Non-agency commercial		29		(2)
	Equity instruments:
		Fixed income mutual funds:
				U.S. government sector fund		319		(5)		-		-
				Real return sector fund		270		(16)		-		-
				Mortgage sector fund		-		-		532		(12)
				Emerging market sector fund		52		(2)		-		-
	Total investments in marketable
			securities		$	836	$	(31)	$	532	$	(12)

Schedule of realized gains and losses on sales from AFS

		Three Months Ended
		June 30,
Available-for-sale securities:		2013		2012
Realized gains on sales	$	5	$	4
Realized losses on sales	$	(1)	$	(1)
Impairment write-downs	$	(30)	$	-

Summary of Contractual Maturities of Available-for-Sale Securities

		Due in 1 Year or				Due after 1 Year				Due after 5 Years
			Less			through 5 Years				through 10 Years				Due after 10 Years					Total
(Dollars in millions)		Amount		Yield		Amount		Yield		Amount		Yield		Amount		Yield		Amount		Yield
Fair Value of Available-for-Sale Securities:
Debt instruments:
U.S. government and
	agency obligations	$	8	0.19	%	$	42	1.50	%	$	23	1.66	%	$	5	3.16	%	$	78	1.52	%
Municipal debt securities			2	2.39			-	-			1	5.57			12	5.69			15	5.17
Certificates of deposit			1,837	0.44			-	-			-	-			-	-			1,837	0.44
Commercial paper			355	0.19			-	-			-	-			-	-			355	0.19
Foreign government debt
	securities		-	-			3	2.93			-	-			-	-			3	2.93
Corporate debt
	securities		6	3.48			36	4.86			68	3.53			39	3.23			149	3.79
Mortgage-backed securities:
	U.S. government agency		-	-			-	-			4	3.92			75	2.99			79	3.05
	Non-agency residential		-	-			-	-			-	-			5	10.84			5	10.84
	Non-agency commercial		-	-			3	3.71			2	1.18			43	3.35			48	3.30
Asset-backed securities			-	-			-	-			9	1.31			10	2.57			19	1.89
Debt instruments total			2,208	0.40			84	3.08			107	2.96			189	3.47			2,588	0.82
Equity instruments:
Fixed income mutual funds																			1,874	3.80
Equity mutual fund																			495	4.09
Equity instruments total			-				-				-				-				2,369	3.86
Total fair value		$	2,208	0.40	%	$	84	3.08	%	$	107	2.96	%	$	189	3.47	%	$	4,957	2.28	%
Total amortized cost		$	2,206			$	83			$	109			$	187			$	4,676