Derivative Instruments (Maturity Of The Notional Amounts Of Derivative Financial Instruments) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	$ 33,971
Remaining Life - 1 - 5 Years	15,189
Remaining Life - 6 - 10 Years	54,468
Remaining Life - 11 - 30 Years	25,874
Remaining Life Over - 30 Years	4,942
Remaining Life - Total Years	134,444
Interest rate contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	11,465	[1]
Remaining Life - 1 - 5 Years	9,727	[1]
Remaining Life - 6 - 10 Years	51,648	[1]
Remaining Life - 11 - 30 Years	24,583	[1]
Remaining Life Over - 30 Years	1,713	[1]
Remaining Life - Total Years	$ 99,136	[1]
Derivative maturity date	Apr. 01, 2067
Foreign currency contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	$ 66	[2]
Remaining Life - 1 - 5 Years	264	[2]
Remaining Life - 6 - 10 Years	764	[2]
Remaining Life - 11 - 30 Years	1,278	[2]
Remaining Life Over - 30 Years	81	[2]
Remaining Life - Total Years	$ 2,453	[2]
Derivative maturity date	Sep. 01, 2049
Equity market contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	$ 22,440
Remaining Life - 1 - 5 Years	5,198
Remaining Life - 6 - 10 Years	1,996
Remaining Life - 11 - 30 Years	13
Remaining Life Over - 30 Years	3,148
Remaining Life - Total Years	32,795
Credit contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life - 6 - 10 Years	60
Remaining Life - Total Years	$ 60

[1] As of March 31, 2019, the latest maturity date for which we were hedging our exposure to the variability in future cash flows for these instruments was April 2067.

[2] As of March 31, 2019, the latest maturity date for which we were hedging our exposure to the variability in future cash flows for these instruments was September 2049.