Accumulated Other Comprehensive Income - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	$ 108	[1]	$ 41	[1]
Tax charge	24		19
Income from continuing operations	86		25
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax			2
Tax charge			1
Income from continuing operations			1
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension and Other Postretirement Benefit Liability Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of actuarial losses	1		2
Amortization of prior service cost	$ (1)

[1] Income (loss) from continuing operations before taxes that are categorized as Unallocated and Other includes: