Debt Repayments of Principal and Interest (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Secured debt	$ 22,073	$ 9,378
Unsecured debt	6,973	1,500
Debt Maturities Repayments Of Interest In Next Twelve Months	766
Debt Maturities Repayments Of Interest After Year Five	141
Debt Maturities Repayments Of Interest In Year Two	540
Debt Maturities Repayments Of Interest In Year Three	293
Debt Maturities Repayments Of Interest In Year Four	168
Debt Maturities Repayments Of Interest In Year Five	64
Interest Payable	1,972
Debt Maturities Repayments Of Principal And Interest In Next Twelve Months	14,360
Debt Maturities Repayments Of Principal And Interest In Year Two	7,013
Debt Maturities Repayments Of Principal And Interest In Year Three	4,492
Debt Maturities Repayments Of Principal And Interest In Year Four	2,505
Debt Maturities Repayments Of Principal And Interest In Year Five	1,757
Debt Maturities Repayments Of Principal And Interest After Year Five	891
Repayments of Principal and Interest	31,018
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	11,492
Long-term Debt, Maturities, Repayments of Principal in Year Two	5,768
Long-term Debt, Maturities, Repayments of Principal in Year Three	3,109
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,337
Long-term Debt, Maturities, Repayments of Principal in Year Five	367
Long-term Debt, Maturities, Repayments of Principal after Year Five	0
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months	2,102
Long-term Debt, Maturities, Repayments of Principal in Year Two	705
Long-term Debt, Maturities, Repayments of Principal in Year Three	1,090
Long-term Debt, Maturities, Repayments of Principal in Year Four	1,000
Long-term Debt, Maturities, Repayments of Principal in Year Five	1,326
Long-term Debt, Maturities, Repayments of Principal after Year Five	$ 750