Retirement Benefit Obligations - Schedule of Allocation of Plan Assets (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,535		$ 1,286
Short-Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	[1]	49	[1]
Domestic Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	87	[1]	65	[1]
International Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	332	[1]	373	[1]
Domestic Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	149	[1]	108	[1]
International Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	543	[1]	304	[1]
Balanced Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	377	[1]	350	[1]
Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41	[1]	37	[1]
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	134		152
Level 1 [Member] | Short-Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 1 [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 1 [Member] | Domestic Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 1 [Member] | International Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	105	[1]	126	[1]
Level 1 [Member] | Domestic Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 1 [Member] | International Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 1 [Member] | Balanced Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 1 [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29	[1]	26	[1]
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,389		1,123
Level 2 [Member] | Short-Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 2 [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6	[1]	49	[1]
Level 2 [Member] | Domestic Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	87	[1]	65	[1]
Level 2 [Member] | International Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	227	[1]	247	[1]
Level 2 [Member] | Domestic Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	149	[1]	108	[1]
Level 2 [Member] | International Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	543	[1]	304	[1]
Level 2 [Member] | Balanced Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	377	[1]	350	[1]
Level 2 [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12		11		16
Level 3 [Member] | Short-Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member] | Domestic Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member] | International Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member] | Domestic Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member] | International Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member] | Balanced Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[1]	0	[1]
Level 3 [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 12	[1]	$ 11	[1]	$ 12

[1] Open-ended pooled funds that are registered and/or available to the general public are valued at the daily published net asset value ("NAV"). Other pooled funds are valued at the NAV provided by the fund issuer.