Financial Instruments Recorded at Other than Fair Value - The carrying amounts and estimated fair values of other financial instruments recorded at other than fair value are as follows: ____________________ (a) At December 31, 2019 and December 31, 2018, approximately $4,211 million and $2,826 million respectively, of the fair value is estimated using a market approach based on quoted market prices for the same or similar issues (Level 2); the balance is estimated using an income approach utilizing a discounted cash flow valuation technique, considering the current credit profile of the debtor (Level 3).