Retirement Benefit Obligations - Summary of Changes in Fair Value of Investments Reflected as Level 3 Assets (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jun. 30, 2014		Jun. 30, 2013
Actual return on plan assets:
Ending balance	$ 1,535		$ 1,286
Other [Member]
Actual return on plan assets:
Ending balance	41	[1]	37	[1]
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	11		16
Actual return on plan assets:
Actual return on plan assets, Relating to assets still held at end of period	2		(1)
Actual return on plan assets, Relating to assets sold during the period	0		0
Purchases, sales, settlements and issuances	(1)		(4)
Transfers in and out of Level 3	0		0
Ending balance	12		11
Level 3 [Member] | Partnership Interests [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	0		4
Actual return on plan assets:
Actual return on plan assets, Relating to assets still held at end of period	0		0
Actual return on plan assets, Relating to assets sold during the period	0		0
Purchases, sales, settlements and issuances	0		(4)
Transfers in and out of Level 3	0		0
Ending balance	0		0
Level 3 [Member] | Other [Member]
Defined Benefit Plan Disclosure [Line Items]
Beginning balance	11	[1]	12
Actual return on plan assets:
Actual return on plan assets, Relating to assets still held at end of period	2		(1)
Actual return on plan assets, Relating to assets sold during the period	0		0
Purchases, sales, settlements and issuances	(1)		0
Transfers in and out of Level 3	0		0
Ending balance	$ 12	[1]	$ 11	[1]

[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.