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Net gains/(losses) on financial instruments classified as available for sale (Details Text) - BRL (R$) R$ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Gainslosses On Financial Instruments Classified As Available For Sale Details Text [Abstract]
Impairment losses	R$ 1,729,039	R$ 2,106,107	R$ 424,522

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- Definition

Net gains/(losses) on financial instruments classified as available for sale (Details Text)

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- Definition

Net gains/(losses) on financial instruments classified as available for sale. - impairment losses

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