v2.4.0.8
Unrealized Losses on Investments Excluding Held to Maturity (Detail) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2014
Jun. 30, 2013
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value $ 6,464 $ 5,506
Less than 12 Months - Unrealized Losses (89) (321)
12 Months or Greater - Fair Value 1,223 544
12 Months or Greater - Unrealized Losses (42) (139)
Total Fair Value 7,687 6,050
Total Unrealized Losses (131) (460)
U.S. government and agency securities
    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 4,161 2,208
Less than 12 Months - Unrealized Losses (29) (84)
12 Months or Greater - Fair Value 850 0
12 Months or Greater - Unrealized Losses 0 0
Total Fair Value 5,011 2,208
Total Unrealized Losses (29) (84)
Foreign government bonds
    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 566 589
Less than 12 Months - Unrealized Losses (4) (18)
12 Months or Greater - Fair Value 21 69
12 Months or Greater - Unrealized Losses (6) (23)
Total Fair Value 587 658
Total Unrealized Losses (10) (41)
Mortgage-backed securities
    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 120 357
Less than 12 Months - Unrealized Losses 0 (12)
12 Months or Greater - Fair Value 61 39
12 Months or Greater - Unrealized Losses (2) (1)
Total Fair Value 181 396
Total Unrealized Losses (2) (13)
Corporate notes and bonds
    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 1,154 1,142
Less than 12 Months - Unrealized Losses (8) (38)
12 Months or Greater - Fair Value 34 27
12 Months or Greater - Unrealized Losses (1) (2)
Total Fair Value 1,188 1,169
Total Unrealized Losses (9) (40)
Municipal securities
    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value   44
Less than 12 Months - Unrealized Losses   (1)
12 Months or Greater - Fair Value   0
12 Months or Greater - Unrealized Losses   0
Total Fair Value   44
Total Unrealized Losses   (1)
Common and preferred stock
    
Unrealized Losses on Investments [Line Items]    
Less than 12 Months - Fair Value 463 1,166
Less than 12 Months - Unrealized Losses (48) (168)
12 Months or Greater - Fair Value 257 409
12 Months or Greater - Unrealized Losses (33) (113)
Total Fair Value 720 1,575
Total Unrealized Losses $ (81) $ (281)