v2.3.0.11
Regulatory Requirements (Significant U.S. Bank Operating Subsidiaries' Capital) (Details) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2011
Dec. 31, 2010
Total capital, amount $ 55,758 $ 54,477
Tier 1 capital, amount 51,007 52,880
Tier 1 leverage, amount    
Total capital, ratio 18.30% 16.50%
Tier 1 capital, ratio 16.70% 16.10%
Tier 1 leverage, ratio 6.00% 6.60%
Morgan Stanley Bank, National Association [Member]
    
Total capital, amount 9,968 9,568
Tier 1 capital, amount 8,462 8,065
Tier 1 leverage, amount 8,462 8,069
Total capital, ratio 17.70% 18.60%
Tier 1 capital, ratio 15.10% 15.70%
Tier 1 leverage, ratio 12.30% 12.10%
Morgan Stanley Trust Private Bank, National Association [Member]
    
Total capital, amount 1,069 909
Tier 1 capital, amount 1,067 909
Tier 1 leverage, amount $ 1,067 $ 909
Total capital, ratio 40.80% 37.40%
Tier 1 capital, ratio 40.80% 37.40%
Tier 1 leverage, ratio 14.20% 12.40%