Derivatives and Hedging Activities Derivatives and Hedging Activities (Schedule of Hedged Items in a Fair Value Hedging Relationship) (Details) - Long-term Borrowings [Member] - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Schedule of Hedged Items in Fair Value Hedging Relationship [Line Items]
Carrying amount of hedged assets/liabilities	$ 12,481	$ 14,244
Cumulative amount of fair value hedging adjustment increasing (decreasing) the carrying amount of hedged assets/liabilities	$ 339	$ 13