Quarterly report pursuant to Section 13 or 15(d)

Changes in Level 3 Instruments Measured on a Recurring Basis (Detail)

v3.4.0.3
Changes in Level 3 Instruments Measured on a Recurring Basis (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning Balance $ 32 $ 64
Transfers into (out of) Level 3 0 0
Net realized and unrealized gains (losses):    
Included in earnings (in investment income) (5) (8)
Included in accumulated other comprehensive income (pre-tax) 0 0
Purchases 0 0
Sales 0 0
Ending Balance 27 56
Marketable securities    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning Balance 0 0
Transfers into (out of) Level 3 0 0
Net realized and unrealized gains (losses):    
Included in earnings (in investment income) 0 0
Included in accumulated other comprehensive income (pre-tax) 0 0
Purchases 0 0
Sales 0 0
Ending Balance 0 0
Other Long-term Investments    
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]    
Beginning Balance 32 64
Transfers into (out of) Level 3 0 0
Net realized and unrealized gains (losses):    
Included in earnings (in investment income) (5) (8)
Included in accumulated other comprehensive income (pre-tax) 0 0
Purchases 0 0
Sales 0 0
Ending Balance $ 27 $ 56