Equity - Stock Repurchases (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended		12 Months Ended
	Jun. 25, 2014	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 04, 2013
Share repurchases
Total number of shares purchased (in shares)		300,000
Average price paid per share (in dollars per share)		$ 98.98		$ 113.36	$ 99.00	$ 79.06
Repurchase of treasury shares				$ 1,123	$ 974	$ 362
Total cash utilized		$ 26		$ 1,097	$ 1,002	$ 346
2013 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program number of shares authorized to be repurchased (shares)							50,000,000
Maximum number of shares authorized for repurchase under stock repurchase plan as percentage of outstanding common stock							18.00%
Share repurchases
Total number of shares purchased (in shares)				9,700,000	10,100,000	4,400,000
Remaining shares available under repurchase program				25,800,000
2011 Repurchase Program
Share repurchases
Total number of shares purchased (in shares)			100,000
Total cash utilized			$ 10
Stock Repurchases
Share repurchases
Repurchase of treasury shares				$ 974	$ 1,123	$ 362
Total cash utilized				$ 1,097	$ 1,000	$ 352
Harold W. McGraw III
Share repurchases
Total number of shares purchased (in shares)	500,000
Average price paid per share (in dollars per share)	$ 82.66
Total cash utilized	$ 41
Repurchase discount	0.35%