Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Schedule of Reconciliation of Level 3 Investments Available-for-Sale Securities (Detail)

v3.4.0.3
Fair Value Measurements - Schedule of Reconciliation of Level 3 Investments Available-for-Sale Securities (Detail) - Investments Available-for-Sale [Member] - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Balance, beginning of period $ 29 $ 27
Purchases of investments available-for-sale 21 5
Payments on investments available-for-sale   (8)
Sale of investments available-for-sale (14) (2)
Gains on investments available-for-sale recorded in earnings 1 1
Losses on investments available-for-sale recorded in OCI 0 0
Balance, end of period $ 37 $ 23