FAIR VALUE MEASUREMENTS Fair Value Inputs Assets Quantitative Information (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	$ 69,907		$ 68,270
Asset derivatives	706		802
Assets, fair value	75,155		73,901
Length of Volatility of Japanese Yen to US Dollar Exchange Rate	10 years		10 years
Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	400		401
Asset derivatives	110		106
Assets, fair value	510		507
Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	67,319		65,573
Fixed Maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	247		249
Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	2,560		2,669
Perpetual securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	150		149
Equity securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	28		28
Equity securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	3		3
Equity securities | Net Asset Value Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	3		3
Equity securities | Net Asset Value Valuation Technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	3		3
Equity securities | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Offered Quotes	$ 1		$ 1
Equity securities | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Offered Quotes	$ 679		$ 677
Equity securities | Assets | Weighted Average | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Offered Quotes	$ 6		$ 6
Mortgage- and asset-backed securities | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	621		602
Mortgage- and asset-backed securities | Fixed Maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	221		223
Mortgage- and asset-backed securities | Fixed Maturities | Consensus Pricing Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	221		223
Mortgage- and asset-backed securities | Fixed Maturities | Consensus Pricing Valuation Technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	221		223
Banks/financial Institutions | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	6,655		6,598
Banks/financial Institutions | Fixed Maturities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	26		26
Banks/financial Institutions | Fixed Maturities | Consensus Pricing Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	26		84
Banks/financial Institutions | Fixed Maturities | Consensus Pricing Valuation Technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	26		26
Banks/financial Institutions | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	2,341		2,438
Banks/financial Institutions | Perpetual securities | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	150		149
Banks/financial Institutions | Perpetual securities | Consensus Pricing Valuation Technique
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	150		149
Banks/financial Institutions | Perpetual securities | Consensus Pricing Valuation Technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	150		149
Foreign currency swaps
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives	637		746
Foreign currency swaps | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives	109		106
Credit default swaps
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives	1
Credit default swaps | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives	1
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Discounted Cash Flow Valuation Technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives	4		8
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Foreign Exchange Rates	20.32%	[1]	20.50%	[1]
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk	0.20%		0.16%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk	1.10%		1.05%
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Discounted Cash Flow Valuation Technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives	105		98
Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Foreign Exchange Rates	20.32%	[1]	20.50%	[1]
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Assets | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Entity Credit Risk	0.93%
Fair Value Inputs, Recovery Rate	36.69%
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Base Correlation	59.00%	[2]
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Base Correlation	62.00%	[2]
Fair Value, Unobservable Input, Base Correlation, CDS Spreads, Recovery Rate | Credit default swaps | Mortgage- and asset-backed securities | Fixed Maturities | Consensus Pricing Valuation Technique | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Asset derivatives	1
Dollar-denominated | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	38,237		36,285
Dollar-denominated | Mortgage- and asset-backed securities | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	244		216
Dollar-denominated | Banks/financial Institutions | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	3,831		3,710
Dollar-denominated | Banks/financial Institutions | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	162		175
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	2.02%	[3]	2.28%	[3]
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	2.39%	[3]	2.70%	[3]
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	2.02%	[3]	2.28%	[3]
Dollar-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	2.39%	[3]	2.70%	[3]
Yen-denominated | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	29,082		29,288
Yen-denominated | Mortgage- and asset-backed securities | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	377		386
Yen-denominated | Banks/financial Institutions | Fixed Maturities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	2,824		2,888
Yen-denominated | Banks/financial Institutions | Perpetual securities
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Available-for-sale Securities	$ 2,179		$ 2,263
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	0.58%	[4]	0.53%	[4]
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), CDS Spreads and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	1.36%	[4]	1.34%	[4]
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Lower Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	0.58%	[4]	0.53%	[4]
Yen-denominated | Fair Value, Unobservable Input, Interest Rates (USD), Interest Rates (JPY), and Foreign Exchange Rates | Foreign currency swaps | Assets | Upper Limit | Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate	1.36%	[4]	1.34%	[4]

[1] Based on 10 year volatility of JPY/USD exchange rate

[2] Range of base correlation for our bespoke tranche for attachment and detachment points corresponding to market indices

[3] Inputs derived from U.S. long-term rates to accommodate long maturity nature of our swaps

[4] Inputs derived from Japan long-term rates to accommodate long maturity nature of our swaps