Lease commitments (Tables)

12 Months Ended

Dec. 31, 2017

Leases1 [Abstract]

Disclosure of Lease Receivables

	2017				2016
	Total future minimum payments	Unearned finance income		Present value	Total future minimum payments	Unearned finance income		Present value
	$m	$m		$m	$m	$m		$m
Lease receivables:
No later than one year	3,523	(326	)	3,197	3,248	(330	)	2,918
Later than one year and no later than five years	7,033	(696	)	6,337	6,563	(702	)	5,861
Later than five years	4,784	(669	)	4,115	4,548	(633	)	3,915
At 31 Dec	15,340	(1,691	)	13,649	14,359	(1,665	)	12,694