XML 177 R164.htm IDEA: XBRL DOCUMENT v3.19.1
Financial Instruments - Fair Value of Financial Instruments Measured at Fair Value on a Recurring Basis (Detail) - TWD ($)
$ in Millions
Dec. 31, 2018
Dec. 31, 2017
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTPL, Held for trading   $ 569.8
Available-for-sale financial assets   98,248.5
Financial assets at FVTPL, mandatorily measured at FVTPL $ 3,504.6  
Financial assets at FVTOCI, investments in debt instruments 103,472.4  
Notes and accounts receivable, net   684,416.6
Financial assets at FVTOCI 107,067.5  
Commercial paper [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   148.3
Level 3 [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTOCI, investments in debt instruments 3,910.7 5,841.4
Measured at fair value on a recurring basis [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   93,374.2
Financial assets at FVTPL 3,504.6  
Financial assets at FVTOCI 107,067.5  
Hedging derivative financial assets   34.4
Hedging derivative financial liabilities 155.8  
Measured at fair value on a recurring basis [member] | Loans and receivables [member]    
Disclosure of detailed information about financial instruments [line items]    
Notes and accounts receivable, net 3,595.1  
Measured at fair value on a recurring basis [member] | Commercial paper [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   148.3
Financial assets at FVTOCI, investments in debt instruments 107.6  
Measured at fair value on a recurring basis [member] | Level 1 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   10,264.1
Financial assets at FVTOCI 11,596.3  
Hedging derivative financial assets   27.0
Hedging derivative financial liabilities 153.9  
Measured at fair value on a recurring basis [member] | Level 2 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   83,110.1
Financial assets at FVTPL 3,504.6  
Financial assets at FVTOCI 91,560.5  
Hedging derivative financial assets   7.4
Hedging derivative financial liabilities 1.9  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Loans and receivables [member]    
Disclosure of detailed information about financial instruments [line items]    
Notes and accounts receivable, net 3,595.1  
Measured at fair value on a recurring basis [member] | Level 2 [member] | Commercial paper [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   148.3
Financial assets at FVTOCI, investments in debt instruments 107.6  
Measured at fair value on a recurring basis [member] | Level 3 [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTOCI 3,910.7  
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTPL, Held for trading   569.8
Financial assets at FVTPL, mandatorily measured at FVTPL 85.3  
Financial liabilities at FVTPL, Held for trading 40.8 26.7
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member] | Cash flow hedges [member]    
Disclosure of detailed information about financial instruments [line items]    
Hedging derivative financial assets 23.5 7.4
Hedging derivative financial liabilities 1.9 15.6
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member] | Level 2 [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTPL, Held for trading   569.8
Financial assets at FVTPL, mandatorily measured at FVTPL 85.3  
Financial liabilities at FVTPL, Held for trading 40.8 26.7
Measured at fair value on a recurring basis [member] | Forward exchange contracts [member] | Level 2 [member] | Cash flow hedges [member]    
Disclosure of detailed information about financial instruments [line items]    
Hedging derivative financial assets 23.5 7.4
Hedging derivative financial liabilities 1.9 15.6
Measured at fair value on a recurring basis [member] | Corporate bonds [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   40,165.2
Financial assets at FVTOCI, investments in debt instruments 40,753.6  
Measured at fair value on a recurring basis [member] | Corporate bonds [member] | Level 2 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   40,165.2
Financial assets at FVTOCI, investments in debt instruments 40,753.6  
Measured at fair value on a recurring basis [member] | Agency bonds/Agency mortgage-backed securities [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   29,235.4
Financial assets at FVTOCI, investments in debt instruments 31,288.8  
Measured at fair value on a recurring basis [member] | Agency bonds/Agency mortgage-backed securities [member] | Level 2 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   29,235.4
Financial assets at FVTOCI, investments in debt instruments 31,288.8  
Measured at fair value on a recurring basis [member] | Asset backed securities [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   13,459.5
Financial assets at FVTOCI, investments in debt instruments 15,670.3  
Measured at fair value on a recurring basis [member] | Asset backed securities [member] | Level 2 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   13,459.5
Financial assets at FVTOCI, investments in debt instruments 15,670.3  
Measured at fair value on a recurring basis [member] | Government bonds [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   7,817.7
Financial assets at FVTOCI, investments in debt instruments 11,151.3  
Measured at fair value on a recurring basis [member] | Government bonds [member] | Level 1 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   7,716.0
Financial assets at FVTOCI, investments in debt instruments 11,006.2  
Measured at fair value on a recurring basis [member] | Government bonds [member] | Level 2 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   101.7
Financial assets at FVTOCI, investments in debt instruments 145.1  
Measured at fair value on a recurring basis [member] | Publicly traded stocks [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   2,548.1
Financial assets at FVTOCI, Investments in equity instruments 590.1  
Measured at fair value on a recurring basis [member] | Publicly traded stocks [member] | Level 1 [member]    
Disclosure of detailed information about financial instruments [line items]    
Available-for-sale financial assets   2,548.1
Financial assets at FVTOCI, Investments in equity instruments 590.1  
Measured at fair value on a recurring basis [member] | Futures Contract [member] | Fair value hedges [member]    
Disclosure of detailed information about financial instruments [line items]    
Hedging derivative financial assets   27.0
Hedging derivative financial liabilities 153.9  
Measured at fair value on a recurring basis [member] | Futures Contract [member] | Level 1 [member] | Fair value hedges [member]    
Disclosure of detailed information about financial instruments [line items]    
Hedging derivative financial assets   $ 27.0
Hedging derivative financial liabilities 153.9  
Measured at fair value on a recurring basis [member] | Agency mortgage backed securities [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTPL, mandatorily measured at FVTPL 3,419.3  
Measured at fair value on a recurring basis [member] | Agency mortgage backed securities [member] | Level 2 [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTPL, mandatorily measured at FVTPL 3,419.3  
Measured at fair value on a recurring basis [member] | Non-publicly traded stocks [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTOCI, Investments in equity instruments 3,910.7  
Measured at fair value on a recurring basis [member] | Non-publicly traded stocks [member] | Level 3 [member]    
Disclosure of detailed information about financial instruments [line items]    
Financial assets at FVTOCI, Investments in equity instruments $ 3,910.7