Long-Term Debt (Scheduled Remaining Maturity Of Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
2013	$ 2,606
2014	16,885
2015	13,903
2016	7,230
2017	5,568
2018 and thereafter	13,914
Derivative, Amount of Hedged Item	595	1,094
Long-term debt	60,701	74,561
Unsecured Debt [Member]
Debt Instrument [Line Items]
2013	798
2014	5,351
2015	5,072
2016	2,247
2017	2,556
2018 and thereafter	12,712
Derivative, Amount of Hedged Item	595	1,094
Long-term debt	29,331	33,650
Unsecured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2013	869
2014	5,540
2015	5,129
2016	2,311
2017	2,633
2018 and thereafter	13,910
Derivative, Amount of Hedged Item	595
Long-term debt	30,987
Unsecured Debt [Member] | Original Issue Discount [Member]
Debt Instrument [Line Items]
2013	(71)
2014	(189)
2015	(57)
2016	(64)
2017	(77)
2018 and thereafter	(1,198)
Derivative, Amount of Hedged Item	0
Long-term debt	(1,656)
Secured Debt [Member]
Debt Instrument [Line Items]
Derivative, Amount of Hedged Item	0	0
Long-term debt	31,370	40,911
Secured Debt [Member] | Long-term Debt [Member]
Debt Instrument [Line Items]
2013	1,808
2014	11,534
2015	8,831
2016	4,983
2017	3,012
2018 and thereafter	1,202
Derivative, Amount of Hedged Item	0
Long-term debt	$ 31,370