XML 47 R45.htm IDEA: XBRL DOCUMENT v2.4.0.8
Investments in Marketable Securities (Realized Gains and Losses On AFS) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2013
Dec. 31, 2012
Realized gains and losses on sales of available-for-sale securities        
Realized gains on sales $ 12 $ 0 $ 28 $ 9
Realized losses on sales 0 0 (3) (2)
Impairment write-downs $ (1) $ 0 $ (54) $ 0