Derivative Instruments (Maturity Of The Notional Amounts Of Derivative Financial Instruments) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year		$ 33,946
Remaining Life - 1 - 5 Years		22,321
Remaining Life - 6 - 10 Years		51,677
Remaining Life - 11 - 30 Years		24,895
Remaining Life Over - 30 Years		4,658
Remaining Life - Total Years		137,497	$ 110,350
Interest rate contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	[1]	12,968
Remaining Life - 1 - 5 Years	[1]	16,828
Remaining Life - 6 - 10 Years	[1]	49,713
Remaining Life - 11 - 30 Years	[1]	23,715
Remaining Life Over - 30 Years	[1]	1,413
Remaining Life - Total Years	[1]	$ 104,637
Derivative maturity date		Apr. 20, 2067
Foreign currency contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year	[2]	$ 102
Remaining Life - 1 - 5 Years	[2]	268
Remaining Life - 6 - 10 Years	[2]	728
Remaining Life - 11 - 30 Years	[2]	1,166
Remaining Life Over - 30 Years	[2]	109
Remaining Life - Total Years	[2]	$ 2,373
Derivative maturity date		Sep. 18, 2049
Equity market contracts [Member]
Maturity of the notional amounts of derivative financial instruments
Remaining Life Less Than 1 Year		$ 20,876
Remaining Life - 1 - 5 Years		5,225
Remaining Life - 6 - 10 Years		1,236
Remaining Life - 11 - 30 Years		14
Remaining Life Over - 30 Years		3,136
Remaining Life - Total Years		$ 30,487

[1] As of December 31, 2018, 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 December 31, 2018, the latest maturity date for which we were hedging our exposure to the variability in future cash flows for these instruments was September 2049.