Derivative Instruments (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 16
Credit Default Swaps Referencing Indices, Sell Protection
Credit Derivatives
Credit Derivative, Maximum Exposure, Undiscounted	248	$ 0
Credit Risk Derivatives, at Fair Value, Net	7	0
Credit Default Swaps Referencing Indices, Sell Protection | NAIC 3
Credit Derivatives
Credit Derivative, Maximum Exposure, Undiscounted	248
Credit Default Swap, Buying Protection
Credit Derivatives
Credit Derivative, Maximum Exposure, Undiscounted	27	0
Credit Risk Derivatives, at Fair Value, Net	$ 0	$ 0