16. Trade and other receivables


	2018 $m		2017 $m
Current
Trade receivables		474		452
Other receivables		27		23
Prepayments		111		74
Loans to and receivables from associates		1		2

		613		551

Trade and other receivables are held at amortised cost.

Trade receivables are non-interest-bearing and are generally on payment terms of up to 30 days. The fair value of trade and other receivables approximates their carrying value.

The maximum exposure to credit risk for trade and other receivables, excluding prepayments, at the end of the reporting period by geographic region is:


	2018 $m		2017 $m
Americas		325		305
EMEAA		125		122
Greater China		52		50

		502		477

The ageing of trade and other receivables, excluding prepayments, at the end of the reporting period is:


	2018							2017
	Gross $m		Credit loss allowance $m			Net $m		Gross $m		Credit loss allowance $m			Net $m
Not past due		356		(1	)		355		333		(1	)		332
Past due 1 to 30 days		71		(1	)		70		68		(2	)		66
Past due 31 to 180 days		86		(9	)		77		82		(7	)		75
Past due more than 180 days		0		0			0		71		(67	)		4

		513		(11	)		502		554		(77	)		477

Trade and other receivables over 180 days past due are written off, but continue to be actively pursued. The credit risk relating to balances not past due is not deemed to be significant.

The movement in the allowance for expected lifetime credit losses of trade and other receivables during the year is as follows:


	2018 $m			2017 $m			2016 $m
At 1 January		(77	)		(69	)		(56	)
Adjustment arising on adoption of IFRS 9		67			—			—
Provided		(28	)		(15	)		(25	)
Amounts written back		0			2			5
Amounts written off		26			6			5
Exchange adjustments		1			(1	)		2

At 31 December		(11	)		(77	)		(69	)