FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets and Liabilities Carried at Cost or Amortized Cost (Details) In Millions, unless otherwise specified	Dec. 31, 2012 USD ($)	Dec. 31, 2012 JPY (¥)	Dec. 31, 2011 USD ($)	Dec. 31, 2011 JPY (¥)	Dec. 31, 2012 Fixed Maturities USD ($)	Dec. 31, 2011 Fixed Maturities USD ($)	Dec. 31, 2012 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2011 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2012 Municipalities Fixed Maturities USD ($)	Dec. 31, 2011 Municipalities Fixed Maturities USD ($)	Dec. 31, 2012 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2011 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2012 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2011 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2012 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2011 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2012 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2011 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2012 Other Corporate Fixed Maturities USD ($)	Dec. 31, 2011 Other Corporate Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 USD ($)	Dec. 31, 2011 Level 1 USD ($)	Dec. 31, 2012 Level 1 Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 Municipalities Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Municipalities Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2012 Level 1 Other Corporate Fixed Maturities USD ($)	Dec. 31, 2011 Level 1 Other Corporate Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 USD ($)	Dec. 31, 2011 Level 2 USD ($)	Dec. 31, 2012 Level 2 Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 Municipalities Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Municipalities Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2012 Level 2 Other Corporate Fixed Maturities USD ($)	Dec. 31, 2011 Level 2 Other Corporate Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 USD ($)	Dec. 31, 2011 Level 3 USD ($)	Dec. 31, 2012 Level 3 Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Government and Agencies Debt Securities Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 Municipalities Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Municipalities Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Mortgage- and asset-backed Securities Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Public Utilities Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Sovereign and Supranational Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Banks/financial Institutions Fixed Maturities USD ($)	Dec. 31, 2012 Level 3 Other Corporate Fixed Maturities USD ($)	Dec. 31, 2011 Level 3 Other Corporate Fixed Maturities USD ($)
Assets:
Cost or Amortized Cost					$ 54,426		$ 32,043		$ 492		$ 90		$ 4,924		$ 3,209		$ 9,211		$ 4,457
Held-to-maturity Securities, fair value					54,841	46,383	32,332	19,071	520	584	94	134	5,051	5,637	3,317	4,165	8,991	11,480	4,536	5,312			32,332	19,071	32,332	19,071	0	0	0	0	0	0	0	0	0	0	0	0			22,445	27,217	0	0	520	584	30	39	5,051	5,637	3,317	4,165	8,991	11,480	4,536	5,312			64	95	0	0	0	0	64	95	0	0	0	0	0	0	0	0
Liabilities:
Notes payable	4,343		3,275
Notes payable (excluding capital leases), fair value	4,992		3,536																		0	0																	0	0																	4,992	3,536
Obligation To Japanese policyholder protection corporation carrying value	23	2,000	71	5,500
Obligation to Japanese policyholder protection corporation fair value	23		71																		0	0																	0	0																	23	71
Total financial instrument liabilities not carried at fair value	4,366		3,346
Liabilities fair value disclosure financial instruments carried at cost	$ 5,015		$ 3,607																		$ 0	$ 0																	$ 0	$ 0																	$ 5,015	$ 3,607