Trade and other receivables

12 Months Ended

Dec. 31, 2017

Disclosure Of Trade And Other Receivables [Line Items]

18 Trade and other receivables

	Non-current		Current		Total		Non-current		Current		Total
		2017		2017		2017		2016		2016		2016
	US$m		US$m		US$m		US$m		US$m		US$m
Trade receivables^(a)		1		2,314		2,315		-		2,283		2,283
Other receivables		526		820		1,346		347		880		1,227
Prepayment of tolling charges to jointly controlled entities^(b)		269		-		269		267		-		267
Pension surpluses (note 44)		871		-		871		625		-		625
Amounts due from equity accounted units		-		30		30		-		31		31
Other prepayments		57		279		336		103		266		369
		1,724		3,443		5,167		1,342		3,460		4,802

(a)	At 31 December 2017, trade and other receivables are stated net of provisions for doubtful debts of US$55 million (2016: US$66 million). Amounts of US$38 million were impaired during the year, and US$11 million of unused provision reversed.

(b)	These prepayments will be charged to Group operating costs as processing takes place.

There is no material element of trade and other receivables that is interest-bearing.

The fair value of current trade and other receivables and the majority of amounts classified as non-current trade and other receivables approximates to their carrying value.

As of 31 December 2017, trade receivables of US$145 million (2016: US$230 million) were past due but not impaired. The ageing of these receivables is as follows:

		2017		2016
	US$m		US$m
less than 30 days overdue		122		196
between 30 and 60 days overdue		3		4
between 60 and 90 days overdue		17		7
more than 90 days overdue		3		23
		145		230

These relate to a number of customers for whom there is no recent history of default.

With respect to trade and other receivables that are neither impaired nor past due, there are no indications as of the reporting date that the debtors will not meet their payment obligations.

Rio Tinto plc [member]

Disclosure Of Trade And Other Receivables [Line Items]

Trade and other receivables

C Trade and other receivables

Trade and other receivables includes US$9,114 million (31 December 2016: US$6,007 million), which is subject to interest based on LIBOR, is unsecured and repayable on demand.