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Fair Values (Details Textuals) - USD ($)
Dec. 31, 2020
Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets measured at fair value for impairment $ 22,260,000,000 $ 8,749,000,000
Fair Value, Measurements, Nonrecurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets measured at fair value for impairment $ 0 $ 0