Derivative Instruments (Maturity Of The Notional Amounts Of Derivative Financial Instruments) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	$ 32,637
Remaining Life - 1 - 5 Years	32,367
Remaining Life - 6 - 10 Years	31,421
Remaining Life - 11 - 30 Years	15,903
Remaining Life Over - 30 Years	2,665
Remaining Life - Total Years	114,993
Interest rate contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	15,024	[1]
Remaining Life - 1 - 5 Years	22,369	[1]
Remaining Life - 6 - 10 Years	30,174	[1]
Remaining Life - 11 - 30 Years	14,926	[1]
Remaining Life Over - 30 Years	1,213	[1]
Remaining Life - Total Years	$ 83,706	[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	$ 19	[2]
Remaining Life - 1 - 5 Years	151	[2]
Remaining Life - 6 - 10 Years	378	[2]
Remaining Life - 11 - 30 Years	962	[2]
Remaining Life Over - 30 Years	10	[2]
Remaining Life - Total Years	$ 1,520	[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	$ 17,594
Remaining Life - 1 - 5 Years	9,784
Remaining Life - 6 - 10 Years	869
Remaining Life - 11 - 30 Years	15
Remaining Life Over - 30 Years	1,442
Remaining Life - Total Years	29,704
Credit contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year
Remaining Life - 1 - 5 Years	63
Remaining Life - 6 - 10 Years
Remaining Life - 11 - 30 Years
Remaining Life Over - 30 Years
Remaining Life - Total Years	$ 63

[1] As of June 30, 2017, 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 June 30, 2017, the latest maturity date for which we were hedging our exposure to the variability in future cash flows for these instruments was September 2049.