Fair Value (Recurring Measurements) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Debt securities:
Unsecured debentures	$ 615	$ 448
Certificates of deposit	137	143
Government debt securities	28	34
Subtotal	780	625
Equity securities:
Mutual funds	57	56
Subtotal	57	56
Total available-for-sale	837	681
Equity securities:
Mutual funds	12	12
Total Trading	12	12
DERIVATIVES:
Total derivatives	105	100
Total assets	954	793
Derivative Liabilities Abstract
Total Derivatives	655	657
Total liabilities	655	657
Interest Rate Derivatives
DERIVATIVES:
Total derivatives	2	2
Derivative Liabilities Abstract
Total Derivatives	541	565
Cross Currency Swaps
DERIVATIVES:
Total derivatives	8	6
Derivative Liabilities Abstract
Total Derivatives	3	6
Foreign Currency
DERIVATIVES:
Total derivatives	88	81
Derivative Liabilities Abstract
Total Derivatives	18	14
Commodity & Other
DERIVATIVES:
Total derivatives	7	11
Derivative Liabilities Abstract
Total Derivatives	93	72
Level 1
Debt securities:
Unsecured debentures	0	0
Certificates of deposit	0	0
Government debt securities	0	0
Subtotal	0	0
Equity securities:
Mutual funds	0	0
Subtotal	0	0
Total available-for-sale	0	0
Equity securities:
Mutual funds	12	12
Total Trading	12	12
DERIVATIVES:
Total derivatives	0	0
Total assets	12	12
Derivative Liabilities Abstract
Total Derivatives	0	0
Total liabilities	0	0
Level 1 | Interest Rate Derivatives
DERIVATIVES:
Total derivatives	0	0
Derivative Liabilities Abstract
Total Derivatives	0	0
Level 1 | Cross Currency Swaps
DERIVATIVES:
Total derivatives	0	0
Derivative Liabilities Abstract
Total Derivatives	0	0
Level 1 | Foreign Currency
DERIVATIVES:
Total derivatives	0	0
Derivative Liabilities Abstract
Total Derivatives	0	0
Level 1 | Commodity & Other
DERIVATIVES:
Total derivatives	0	0
Derivative Liabilities Abstract
Total Derivatives	0	0
Level 2
Debt securities:
Unsecured debentures	615	448
Certificates of deposit	137	143
Government debt securities	28	34
Subtotal	780	625
Equity securities:
Mutual funds	57	56
Subtotal	57	56
Total available-for-sale	837	681
Equity securities:
Mutual funds	0	0
Total Trading	0	0
DERIVATIVES:
Total derivatives	22	18
Total assets	859	699
Derivative Liabilities Abstract
Total Derivatives	503	179
Total liabilities	503	179
Level 2 | Interest Rate Derivatives
DERIVATIVES:
Total derivatives	2	2
Derivative Liabilities Abstract
Total Derivatives	469	153
Level 2 | Cross Currency Swaps
DERIVATIVES:
Total derivatives	8	6
Derivative Liabilities Abstract
Total Derivatives	3	6
Level 2 | Foreign Currency
DERIVATIVES:
Total derivatives	6	2
Derivative Liabilities Abstract
Total Derivatives	7	7
Level 2 | Commodity & Other
DERIVATIVES:
Total derivatives	6	8
Derivative Liabilities Abstract
Total Derivatives	24	13
Level 3
Debt securities:
Unsecured debentures	0	0
Certificates of deposit	0	0
Government debt securities	0	0
Subtotal	0	0
Equity securities:
Mutual funds	0	0
Subtotal	0	0
Total available-for-sale	0	0
Equity securities:
Mutual funds	0	0
Total Trading	0	0
DERIVATIVES:
Total derivatives	83	82
Total assets	83	82
Derivative Liabilities Abstract
Total Derivatives	152	478
Total liabilities	152	478
Level 3 | Interest Rate Derivatives
DERIVATIVES:
Total derivatives	0	0
Derivative Liabilities Abstract
Total Derivatives	72	412
Level 3 | Cross Currency Swaps
DERIVATIVES:
Total derivatives	0	0
Derivative Liabilities Abstract
Total Derivatives	0	0
Level 3 | Foreign Currency
DERIVATIVES:
Total derivatives	82	79
Derivative Liabilities Abstract
Total Derivatives	11	7
Level 3 | Commodity & Other
DERIVATIVES:
Total derivatives	1	3
Derivative Liabilities Abstract
Total Derivatives	$ 69	$ 59