Arrangements With Off-Balance Sheet Risk (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Offsetting capital lease obligation and IRB asset	$ 271	$ 271
ULA [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Indemnification Agreement, Payments	33
ULA [Member] | Deferred Support and Production Costs [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Litigation Settlement, Amount Awarded from Other Party	$ 307