Investments held to maturity (Details 1) - BRL (R$) R$ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Securities:
Brazilian government securities	R$ 26,738,940	R$ 30,241,947
Corporate debt securities	12,259,564	12,739,187
Brazilian sovereign bonds	7,614	20,894
Total	39,006,118	43,002,028
Gross unrealized gains
Securities:
Brazilian government securities	2,442,844	2,918,273
Corporate debt securities	126,092	28,750
Brazilian sovereign bonds	0	878
Total	2,568,936	2,947,901
Gross unrealized losses
Securities:
Brazilian government securities	(6,489)	(306,566)
Corporate debt securities	(421,874)	(1,388,614)
Brazilian sovereign bonds	(420)	0
Total	(428,783)	(1,695,180)
Fair value
Securities:
Brazilian government securities	29,175,295	32,853,654
Corporate debt securities	11,963,782	11,379,323
Brazilian sovereign bonds	7,194	21,772
Total	R$ 41,146,271	R$ 44,254,749

The amount of non-derivative financial assets with fixed or determinable payments and fixed maturity that an entity has the positive intention and ability to hold to maturity other than: (a) those that the entity upon initial recognition designates as at fair value through profit or loss; (b) those that the entity designates as available for sale; and (c) those that meet the definition of loans and receivables. An entity shall not classify any financial assets as held to maturity if the entity has, during the current financial year or during the two preceding financial years, sold or reclassified more than an insignificant amount of held-to-maturity investments before maturity (more than insignificant in relation to the total amount of held-to-maturity investments) other than sales or reclassifications that: (i) are so close to maturity or the financial asset’s call date (for example, less than three months before maturity) that changes in the market rate of interest would not have a significant effect on the financial asset’s fair value; (ii) occur after the entity has collected substantially all of the financial asset’s original principal through scheduled payments or prepayments; or (iii) are attributable to an isolated event that is beyond the entity’s control, is non-recurring and could not have been reasonably anticipated by the entity. [Refer: Derivative financial assets; Held-to-maturity investments; Prepayments]

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Note Expiry date 2018-01-01
-Name IFRS
-Number 7
-IssueDate 2017-01-01
-Paragraph 8
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=7&date=2017-03-02&anchor=para_8_b&doctype=Standard&book=B
-URIDate 2017-03-09

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant