Long-Term Debt (Scheduled Remaining Maturity Of Long-Term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
2015	$ 3,725
2016	12,010
2017	18,710
2018	11,767
2019	7,112
2020 and thereafter	13,692
Derivative, Amount of Hedged Item	445	$ 452
Long-term debt	67,461	66,558
Unsecured Debt [Member]
Debt Instrument [Line Items]
2015	(6)
2016	1,860
2017	4,307
2018	2,854
2019	1,591
2020 and thereafter	8,649
Derivative, Amount of Hedged Item	445	452
Long-term debt	19,700	22,415
Unsecured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2015	11
2016	1,934
2017	4,393
2018	2,951
2019	1,625
2020 and thereafter	9,741
Derivative, Amount of Hedged Item	445
Long-term debt	21,100
Unsecured Debt [Member] | Original Issue Discount [Member]
Debt Instrument [Line Items]
2015	(17)
2016	(74)
2017	(86)
2018	(97)
2019	(34)
2020 and thereafter	(1,092)
Derivative, Amount of Hedged Item	0
Long-term debt	(1,400)
Secured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	0	0
Long-term debt	47,761	$ 44,143
Secured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2015	3,731
2016	10,150
2017	14,403
2018	8,913
2019	5,521
2020 and thereafter	5,043
Derivative, Amount of Hedged Item	0
Long-term debt	$ 47,761