Long-Term Debt (Scheduled Remaining Maturity Of Long-Term Debt) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
2016	$ 5,259
2017	16,417
2018	12,136
2019	8,808
2020	6,262
2021 and thereafter	11,621
Derivative, Amount of Hedged Item	537	$ 331
Long-term debt	61,040	66,234
Unsecured Debt [Member]
Debt Instrument [Line Items]
2016	1,379
2017	4,277
2018	3,600
2019	1,613
2020	2,175
2021 and thereafter	8,002
Derivative, Amount of Hedged Item	520	334
Long-term debt	21,566	20,966
Unsecured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2016	1,419
2017	4,365
2018	3,700
2019	1,650
2020	2,212
2021 and thereafter	9,067
Derivative, Amount of Hedged Item	520
Long-term debt	22,933
Unsecured Debt [Member] | Original Issue Discount [Member]
Debt Instrument [Line Items]
2016	(40)
2017	(88)
2018	(100)
2019	(37)
2020	(37)
2021 and thereafter	(1,065)
Derivative, Amount of Hedged Item	0
Long-term debt	(1,367)
Secured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	17	(3)
Long-term debt	39,474	$ 45,268
Secured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2016	3,880
2017	12,140
2018	8,536
2019	7,195
2020	4,087
2021 and thereafter	3,619
Derivative, Amount of Hedged Item	17
Long-term debt	$ 39,474