Derivative Instruments (Maturity Of The Notional Amounts Of Derivative Financial Instruments) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	$ 29,366
Remaining Life - 1 - 5 Years	34,161
Remaining Life - 6 - 10 Years	31,424
Remaining Life - 11 - 30 Years	15,188
Remaining Life Over - 30 Years	2,487
Remaining Life - Total Years	112,626
Interest rate contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	12,032	[1]
Remaining Life - 1 - 5 Years	25,178	[1]
Remaining Life - 6 - 10 Years	29,368	[1]
Remaining Life - 11 - 30 Years	14,478	[1]
Remaining Life Over - 30 Years	1,213	[1]
Remaining Life - Total Years	$ 82,269	[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	$ 37	[2]
Remaining Life - 1 - 5 Years	151	[2]
Remaining Life - 6 - 10 Years	355	[2]
Remaining Life - 11 - 30 Years	695	[2]
Remaining Life Over - 30 Years		[2]
Remaining Life - Total Years	$ 1,238	[2]
Derivative maturity date	Dec. 01, 2045
Equity market contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	$ 17,297
Remaining Life - 1 - 5 Years	8,832
Remaining Life - 6 - 10 Years	1,645
Remaining Life - 11 - 30 Years	15
Remaining Life Over - 30 Years	1,274
Remaining Life - Total Years	29,063
Credit contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year
Remaining Life - 1 - 5 Years
Remaining Life - 6 - 10 Years	56
Remaining Life - 11 - 30 Years
Remaining Life Over - 30 Years
Remaining Life - Total Years	$ 56

[1] As of March 31, 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 March 31, 2017, the latest maturity date for which we were hedging our exposure to the variability in future cash flows for these instruments was December 2045.