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Fair Value Information (Narrative) (Details) - USD ($)
$ in Millions
Sep. 30, 2021
Dec. 31, 2020
Fair Value, Inputs, Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Redeemable Preferred Securities Of Subsidiaries Fair Value Disclosure $ 28 $ 28
Fair Value, Measurements, Recurring | Net Asset Value or Its Equivalent    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Cash Surrender Value, Fair Value Disclosure 73 73
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis    
Derivatives Assets 79 44
Derivatives Liability $ 39 $ 92