Long-Term Debt (Long-Term Debt Portfolio) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	$ 18,370	$ 17,172
Long-term Debt, Excluding Current Maturities	48,515	51,848
Derivative, Amount of Hedged Item	414	445
Long-term debt	67,299	69,465
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	6,572	5,321
Long-term Debt, Excluding Current Maturities	17,065	21,425
Derivative, Amount of Hedged Item	414	445
Long-term debt	24,051	27,191
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	11,798	11,851
Long-term Debt, Excluding Current Maturities	31,450	30,423
Derivative, Amount of Hedged Item	0	0
Long-term debt	43,248	42,274
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Instrument [Line Items]
Long-term Debt, Excluding Current Maturities	$ 2,600	$ 2,600