XML 161 R154.htm IDEA: XBRL DOCUMENT v3.8.0.1
Post-Retirement Obligation - Summary of Changes in Net Liabilities (Detail) - BRL (R$)
R$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of defined benefit plans [line items]      
Current liabilities R$ 232 R$ 199  
Non-currentliabilities 3,954 4,043  
Net liabilities, Beginning balance 4,242 3,253 R$ 2,631
Expense recognized in Statement of income 455 448 359
Contributions paid (282) (240) (208)
Plan amendment - Past service (619)   (74)
Actuarial losses (gains) 390 781 545
Net liabilities, Ending balance 4,186 4,242 3,253
Pension plans and retirement supplement plans [member]      
Disclosure of defined benefit plans [line items]      
Net liabilities, Beginning balance 1,679 1,346 798
Expense recognized in Statement of income 175 187 129
Contributions paid (160) (128) (116)
Actuarial losses (gains) 374 274 535
Net liabilities, Ending balance 2,068 1,679 1,346
Health plan [member]      
Disclosure of defined benefit plans [line items]      
Net liabilities, Beginning balance 1,711 1,323 1,120
Expense recognized in Statement of income 189 182 142
Contributions paid (113) (99) (77)
Actuarial losses (gains) 22 305 138
Net liabilities, Ending balance 1,809 1,711 1,323
Dental plan [member]      
Disclosure of defined benefit plans [line items]      
Net liabilities, Beginning balance 38 30 33
Expense recognized in Statement of income 3 4 4
Contributions paid (2) (2) (3)
Actuarial losses (gains) (1) 6 (4)
Net liabilities, Ending balance 38 38 30
Life insurance [member]      
Disclosure of defined benefit plans [line items]      
Net liabilities, Beginning balance 814 554 680
Expense recognized in Statement of income 88 75 84
Contributions paid (7) (11) (12)
Plan amendment - Past service (619)   (74)
Actuarial losses (gains) (5) 196 (124)
Net liabilities, Ending balance R$ 271 R$ 814 R$ 554