Long-Term Debt (Scheduled Remaining Maturity Of Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
2014	$ 10,400
2015	17,829
2016	11,936
2017	11,561
2018	4,479
2019 and thereafter	11,631
Derivative, Amount of Hedged Item	459	445
Long-term debt	68,295	69,465
Unsecured Debt [Member]
Debt Instrument [Line Items]
2014	2,367
2015	5,101
2016	1,868
2017	3,968
2018	1,186
2019 and thereafter	8,983
Derivative, Amount of Hedged Item	459	445
Long-term debt	23,932	27,191
Unsecured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2014	2,511
2015	5,161
2016	1,934
2017	4,046
2018	1,278
2019 and thereafter	10,091
Derivative, Amount of Hedged Item	459
Long-term debt	25,480
Unsecured Debt [Member] | Original Issue Discount [Member]
Debt Instrument [Line Items]
2014	(144)
2015	(60)
2016	(66)
2017	(78)
2018	(92)
2019 and thereafter	(1,108)
Derivative, Amount of Hedged Item	0
Long-term debt	(1,548)
Secured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	0	0
Long-term debt	44,363	42,274
Secured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2014	8,033
2015	12,728
2016	10,068
2017	7,593
2018	3,293
2019 and thereafter	2,648
Derivative, Amount of Hedged Item	0
Long-term debt	$ 44,363