Investments in Marketable Securities (Tables)

3 Months Ended

Dec. 31, 2013

Investments in Marketable Securities [Abstract]

Summary of Investments in Marketable Securities

				December 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		$	87	$	1	$	(1)	$	87
		Municipal debt securities			14		-		-		14
		Certificates of deposit			1,533		-		-		1,533
		Commercial paper			125		-		-		125
		Foreign government debt securities			3		-		-		3
		Corporate debt securities			151		4		(2)		153
		Mortgage-backed securities:
			U.S. government agency		64		1		(1)		64
			Non-agency residential		4		1		-		5
			Non-agency commercial		51		-		(1)		50
		Asset-backed securities			23		-		-		23
	Equity instruments:
		Fixed income mutual funds:
			Short-term sector fund		41		3		-		44
			U.S. government sector fund		343		-		(6)		337
			Municipal sector fund		21		-		-		21
			Investment grade corporate sector fund		284		28		(2)		310
			High-yield sector fund		36		7		-		43
			Real return sector fund		275		-		(7)		268
			Mortgage sector fund		567		-		(9)		558
			Asset-backed securities sector fund		40		9		-		49
			Emerging market sector fund		64		1		(1)		64
			International sector fund		170		1		(1)		170
		Equity mutual fund			241		288		-		529
Total investments in marketable securities				$	4,137	$	344	$	(31)	$	4,450

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
				December 31, 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	$	43	$	(1)	$	-	$	-
		Corporate debt securities			81		(2)		-		-
		Mortgage backed securities:
			U.S. government agency		30		(1)		-		-
			Non-agency commercial		17		(1)		-		-
	Equity instruments:
		Fixed income mutual funds:
			U.S. government sector fund		337		(6)		-		-
			Investment grade corporate sector fund		310		(2)		-		-
			Real return sector fund		268		(7)		-		-
			Mortgage sector fund		558		(9)		532		(12)
			Emerging market sector fund		64		(1)		-		-
			International sector fund		170		(1)		-		-
	Total investments in marketable
		securities		$	1,878	$	(31)	$	532	$	(12)

Schedule of realized gains and losses on sales from AFS

		Three Months Ended				Nine Months Ended
		December 31,				December 31,
(Dollars in millions)		2013		2012		2013		2012
Available-for-sale securities:
	Realized gains on sales	$	12	$	-	$	28	$	9
	Realized losses on sales	$	-	$	-	$	(3)	$	(2)
	Impairment write-downs	$	(1)	$	-	$	(54)	$	0

Summary of Contractual Maturities of Available-for-Sale Securities

		Due in 1 Year or				Due after 1 Year				Due after 5 Years				Due after
			less			through 5 years				through 10 years				10 years					Total
(Dollars in millions)		Amount		Yield		Amount		Yield		Amount		Yield		Amount		Yield		Amount		Yield
Available-for-Sale Securities:
Debt instruments:
	U.S. government and
	agency obligations	$	-	-	%	$	65	1.50	%	$	21	1.61	%	$	1	3.57	%	$	87	1.55	%
	Municipal debt securities		2	2.39			-	-			1	5.57			11	5.69			14	5.18
	Certificates of deposit		1,533	0.29			-	-			-	-			-	-			1,533	0.29
	Commercial paper		125	0.23			-	-			-	-			-	-			125	0.23
	Foreign government debt
	securities		3	2.93			-	-			-	-			-	-			3	2.93
	Corporate debt
	securities		7	4.14			49	4.31			71	3.55			26	4.39			153	3.97
	Mortgage-backed securities:
	U.S. government agency		-	-			-	-			4	3.91			60	3.24			64	3.28
	Non-agency residential		-	-			-	-			-	-			5	10.17			5	10.17
	Non-agency commercial		-	-			3	1.87			1	3.64			46	3.35			50	3.29
	Asset-backed securities		-	-			5	0.75			4	1.87			14	2.54			23	1.97
Debt instruments total			1,670	0.31			122	2.62			102	3.15			163	3.75			2,057	0.86
Equity instruments:
	Fixed income mutual funds																		1,864	5.56
	Equity mutual fund																		529	4.29
Equity instruments total			-				-				-				-				2,393	5.28
Total fair value		$	1,670	0.31	%	$	122	2.62	%	$	102	3.15	%	$	163	3.75	%	$	4,450	3.24	%
Total amortized cost		$	1,670			$	119			$	104			$	162			$	4,137